The reserve is named in honor of Karen Mogensen who, with her husband Nicolas Wessberg, founded the national park system in Costa Rica. Karen died in 1994, Soon After ASEPALECO Was Established, the ecological association that manages and protect the Karen Mogensen reserve.

In the 1950s and 60s, the Nicoya Peninsula was heavily logged to make way for cattle farming, in response to the boom of the beef industry, and the virgin forest was disappearing at an alarming rate. By the 1990s, only 21% of the peninsula’s forest remained. The need to secure this precious ecosystem was urgent, for many reasons.

In 1991 a small group of passionate nature conservationists, spearheaded by Luis Mena, had the vision to buy land to protect the forests and regenerate pasture lands. The initial land purchase to create the reserve was bought up in 1996 with the help of Nepenthes from Denmark to successfully buy and protect 364 hectares of agricultural and cattle land, with patches of secondary and old-growth forest at the heart center of the Nicoya Peninsula.

This initial purchase of land was the first move in a strategic battle, fighting back against deforestation. The boundaries that were established have, since 1996, gained ground with the forest reserve tripling in size. Currently, the reserve Encompasses over a 1000 hectares- over 24710acres
– an incredible achievement that is the result of extreme perseverance and commitment to conservation.