Costa Rica–Nicaragua border

The Costa Rica–Nicaragua border is the 309 kilometres (192 mi) long international border, extending east–west, between the Caribbean Sea (E) and the Pacific Ocean (W) it separates the northern part of Costa Rica from the Southern part of Nicaragua.

The southern bank of the River San Juan lies on the border for much of its length.

The border separates, from east to west: Costa Rica and Nicaragua were part of the United Provinces of Central America between 1823 and 1838.

This provided a justification for entry of Nicaraguan military personnel into Costa Rica.

The true border is based on the Cañas-Jerez Treaty of 1858 and the Cleveland Award of 1888.