The climate of the region is humid and tropical, thanks to the moderating influence of the river. The average annual temperature is 19 °C.[4]​.

Although the area has a temperate subhumid climate, due to the influence of the waters, in this case the Paraná River and the tributaries of the Río de la Plata, a moderating effect is produced that influences the main climatic variables, which determines a humid tropical climate. This is one of the main reasons that made the area a tropical garden in latitudes conducive to other types of flora, such as that which appears in adjacent areas.

Flora

The island sector has forests of ceibos and curupíes "Curupí (plant)") and forests of timbó blanco. The lower parts are covered with dense grasslands with roofing straw and boba straw, with some reflecting pools.

Fauna

The fauna is made up mainly of [mammals], aquatic [reptiles] and [birds]. Among the mammals, the capybaras (Hydrochoerus hydrochaeris) stand out, whose footprints can be seen on the trails, otters (Lutrinae) and river otters (Lontra longicaudis); Among the reptiles you can find the yacaré ñato") (a species that was believed to be extinct), the monkey lizard (Tupinambis teguixin), aquatic snakes") and lagoon turtles.[4]​.

The bird species are very varied, highlighting the reddish quillfish (which builds its nests with sticks, which hang over the water), ducks (Anatidae), caraús (Aramus guarauna), chajás (Chauna torquata), storks (Ciconiidae), herons (Ardeidae) and also kingfishers (Chloroceryle sp.), which They are abundant and easy to observe, which is why they have become the most representative species in the park.[4]​.

On October 16, 1986, the Chamber of Deputies of the Nation approved a declaration presented by the deputy for Entre Ríos Rodolfo Miguel Parente, by which the Executive Branch was requested to study the possibility of creating a national park in the Diamante area. On May 7, 1987, the deliberative council of the municipality of Diamante sanctioned ordinance No. 14/1987, donating the domain to the National State of 2,458 hectares 62 to 74 ca. of islands and swamps located in its ejido with the aim of them being used for the creation of a park or nature reserve. On May 8, 1987, Mayor Humberto Ré promulgated it by municipal decree No. 242/1987. On September 23, 1987, the municipality of Diamante and the National Parks Administration signed an agreement for collaboration and mutual advice to evaluate the possible creation of a national park. On November 19, 1987, the agreement was approved by ordinance No. 67/1987, promulgated by decree No. 713/1987 on December 28, 1987. On January 11, 1990, another agreement was signed with the participation of the government of Entre Ríos, approved by ordinance No. 291/1990 on April 11 and promulgated by decree No. 169/1990 on April 19, creating the Administrative Commission of the Pre-Delta Protected Natural Area.[8]​.

On July 23, 1991, provincial law No. 8491 was approved - promulgated on August 8 -, by which jurisdiction over the fraction of land donated by the municipality of Diamante was transferred to the National State:[9]​.

On the basis of a bill presented by national deputy Parente,[10]​ on December 19, 1991, Law No. 24063 was passed creating this national park, which was actually promulgated on January 13, 1992, and published in the Official Gazette on January 20, 1992.[11]​.

The purpose was to preserve a part of the environments of the upper delta of the Paraná River.[4]​[5]​[6]​[7]​.

On May 19, 1992, the formal inauguration and takeover ceremony by the National Parks Administration took place. On April 1, 1997, the administration of the national park was made independent of that of the El Palmar national park, and a mayor was appointed.

By resolution No. 122/98 of August 20, 1998, the National Parks Administration decided to approve a List of Vertebrates of Special Value of the Predelta National Park, composed of: 10 birds, 5 mammals, 3 reptiles, and one amphibian.[12]​.

On December 14, 2009, the National Parks Administration acquired the Coronel Sarmiento National Field from the Argentine Army, located adjacent to the Pre-Delta national park and which has an area of ​​146 ha 29 to 31 ca. This field has conservation interest and can be used to build the service area of ​​the national park, given that it is located on dry land above the ravines and with easy access from Diamante. By means of provincial law No. 10193 passed on December 20, 2012 and promulgated on December 26, Campo Nacional Coronel Sarmiento was disaffected from the Diamante municipal ejido, to be transferred its jurisdiction to the National State with the aim of incorporating it into the Pre-Delta national park. The law set a period of 4 years from its publication for the National Congress to sanction the law, accepting the transfer of jurisdiction, a period that was met on January 8, 2017, becoming void.[13] The field was leased by the Argentine Army to a private lessee who took legal action. Although the National Parks Administration has control of the field and carries out preservation actions there, when the transfer law expires, jurisdiction over the field continues to belong to the province of Entre Ríos, which is why it could not be incorporated into the national park by virtue of the requirement provided for in the regime of law no. 22351.[14]​.

On June 30, 2022, national law No. 27672 was passed, which accepted the transfer of jurisdiction carried out by the province of Entre Ríos to the national state.

By resolution No. 126/2011 of the National Parks Administration dated May 19, 2011, it was established that Pre-Delta would fall for administrative purposes in the category protected areas of complexity III, for which the national park is headed by a designated intendant, to whom 4 departments depend (Administration; Works and Maintenance; National Park Rangers; Conservation and Public Use) and the Dispatch Division and Entry, Departure, and Notification Desk.[17] The mayor's office has its headquarters in the city of Diamante and simultaneously administers the Islas de Santa Fe national park.

Combination of aquatic environments (lagoons, streams, swamps) together with ravines, represent an element of great beauty in themselves, giving a very particular scenic attraction to the national park. Recreational activities are concentrated in this area, since being delimited by river courses limits internal circulation problems that prevent the free mobility of visitors within the rest of the protected area. The Paraje La Jaula, 5 km from the city of Diamante, is the only point that can be entered by land, via a local road. The characteristic environments of the rest of the national park are represented there. The main activities carried out by the visitor are: hiking along trails, coastal sport fishing, camping, and bird watching. You can also see the islands that make up the national park; El Ceibo, Las Mangas, del Barro.

Due to the characteristics of the park, mainly made up of islands, most activities must be carried out in appropriate boats. However, the National Parks Administration created two interpretive trails and a camp in the Paraje La Jaula, where there are campfires.[4]​[18]​.

• - National System of Protected Areas of Argentina.

• - Protected natural areas of Argentina.

• - Wikimedia Commons hosts a multimedia category on Pre-Delta National Park.

• - File in SIB.

• - Federal System of Protected Areas.

The climate of the region is humid and tropical, thanks to the moderating influence of the river. The average annual temperature is 19 °C.[4]​.

Although the area has a temperate subhumid climate, due to the influence of the waters, in this case the Paraná River and the tributaries of the Río de la Plata, a moderating effect is produced that influences the main climatic variables, which determines a humid tropical climate. This is one of the main reasons that made the area a tropical garden in latitudes conducive to other types of flora, such as that which appears in adjacent areas.

Flora

The island sector has forests of ceibos and curupíes "Curupí (plant)") and forests of timbó blanco. The lower parts are covered with dense grasslands with roofing straw and boba straw, with some reflecting pools.

Fauna

The fauna is made up mainly of [mammals], aquatic [reptiles] and [birds]. Among the mammals, the capybaras (Hydrochoerus hydrochaeris) stand out, whose footprints can be seen on the trails, otters (Lutrinae) and river otters (Lontra longicaudis); Among the reptiles you can find the yacaré ñato") (a species that was believed to be extinct), the monkey lizard (Tupinambis teguixin), aquatic snakes") and lagoon turtles.[4]​.

The bird species are very varied, highlighting the reddish quillfish (which builds its nests with sticks, which hang over the water), ducks (Anatidae), caraús (Aramus guarauna), chajás (Chauna torquata), storks (Ciconiidae), herons (Ardeidae) and also kingfishers (Chloroceryle sp.), which They are abundant and easy to observe, which is why they have become the most representative species in the park.[4]​.

On October 16, 1986, the Chamber of Deputies of the Nation approved a declaration presented by the deputy for Entre Ríos Rodolfo Miguel Parente, by which the Executive Branch was requested to study the possibility of creating a national park in the Diamante area. On May 7, 1987, the deliberative council of the municipality of Diamante sanctioned ordinance No. 14/1987, donating the domain to the National State of 2,458 hectares 62 to 74 ca. of islands and swamps located in its ejido with the aim of them being used for the creation of a park or nature reserve. On May 8, 1987, Mayor Humberto Ré promulgated it by municipal decree No. 242/1987. On September 23, 1987, the municipality of Diamante and the National Parks Administration signed an agreement for collaboration and mutual advice to evaluate the possible creation of a national park. On November 19, 1987, the agreement was approved by ordinance No. 67/1987, promulgated by decree No. 713/1987 on December 28, 1987. On January 11, 1990, another agreement was signed with the participation of the government of Entre Ríos, approved by ordinance No. 291/1990 on April 11 and promulgated by decree No. 169/1990 on April 19, creating the Administrative Commission of the Pre-Delta Protected Natural Area.[8]​.

On July 23, 1991, provincial law No. 8491 was approved - promulgated on August 8 -, by which jurisdiction over the fraction of land donated by the municipality of Diamante was transferred to the National State:[9]​.

On the basis of a bill presented by national deputy Parente,[10]​ on December 19, 1991, Law No. 24063 was passed creating this national park, which was actually promulgated on January 13, 1992, and published in the Official Gazette on January 20, 1992.[11]​.

The purpose was to preserve a part of the environments of the upper delta of the Paraná River.[4]​[5]​[6]​[7]​.

On May 19, 1992, the formal inauguration and takeover ceremony by the National Parks Administration took place. On April 1, 1997, the administration of the national park was made independent of that of the El Palmar national park, and a mayor was appointed.

By resolution No. 122/98 of August 20, 1998, the National Parks Administration decided to approve a List of Vertebrates of Special Value of the Predelta National Park, composed of: 10 birds, 5 mammals, 3 reptiles, and one amphibian.[12]​.

On December 14, 2009, the National Parks Administration acquired the Coronel Sarmiento National Field from the Argentine Army, located adjacent to the Pre-Delta national park and which has an area of ​​146 ha 29 to 31 ca. This field has conservation interest and can be used to build the service area of ​​the national park, given that it is located on dry land above the ravines and with easy access from Diamante. By means of provincial law No. 10193 passed on December 20, 2012 and promulgated on December 26, Campo Nacional Coronel Sarmiento was disaffected from the Diamante municipal ejido, to be transferred its jurisdiction to the National State with the aim of incorporating it into the Pre-Delta national park. The law set a period of 4 years from its publication for the National Congress to sanction the law, accepting the transfer of jurisdiction, a period that was met on January 8, 2017, becoming void.[13] The field was leased by the Argentine Army to a private lessee who took legal action. Although the National Parks Administration has control of the field and carries out preservation actions there, when the transfer law expires, jurisdiction over the field continues to belong to the province of Entre Ríos, which is why it could not be incorporated into the national park by virtue of the requirement provided for in the regime of law no. 22351.[14]​.

On June 30, 2022, national law No. 27672 was passed, which accepted the transfer of jurisdiction carried out by the province of Entre Ríos to the national state.

By resolution No. 126/2011 of the National Parks Administration dated May 19, 2011, it was established that Pre-Delta would fall for administrative purposes in the category protected areas of complexity III, for which the national park is headed by a designated intendant, to whom 4 departments depend (Administration; Works and Maintenance; National Park Rangers; Conservation and Public Use) and the Dispatch Division and Entry, Departure, and Notification Desk.[17] The mayor's office has its headquarters in the city of Diamante and simultaneously administers the Islas de Santa Fe national park.

Combination of aquatic environments (lagoons, streams, swamps) together with ravines, represent an element of great beauty in themselves, giving a very particular scenic attraction to the national park. Recreational activities are concentrated in this area, since being delimited by river courses limits internal circulation problems that prevent the free mobility of visitors within the rest of the protected area. The Paraje La Jaula, 5 km from the city of Diamante, is the only point that can be entered by land, via a local road. The characteristic environments of the rest of the national park are represented there. The main activities carried out by the visitor are: hiking along trails, coastal sport fishing, camping, and bird watching. You can also see the islands that make up the national park; El Ceibo, Las Mangas, del Barro.

Due to the characteristics of the park, mainly made up of islands, most activities must be carried out in appropriate boats. However, the National Parks Administration created two interpretive trails and a camp in the Paraje La Jaula, where there are campfires.[4]​[18]​.

• - National System of Protected Areas of Argentina.

• - Protected natural areas of Argentina.

• - Wikimedia Commons hosts a multimedia category on Pre-Delta National Park.

• - File in SIB.

• - Federal System of Protected Areas.