Border Field State Park contains much of the Tijuana River National Estuarine Research Reserve, an important wildlife habitat. The salt and freshwater marshes give refuge to migrating waterfowl and resident wading birds, such as black-necked stilt, avocet, teal, American widgeon and pelican. The park offers hiking, horse trails, surf fishing and birding.
The Treaty of Guadalupe Hidalgo was concluded on February 2, 1848, officially ending the war with Mexico. It provided that the new international border between the two countries be established by a United States and Mexican Boundary Commission. Both commissions surveyed and located the initial borderline at Border Field.