Allenspark is an unincorporated town, a post office, and a census-designated place located in and governed by Boulder County, Colorado, United States. The CDP is a part of the Boulder, CO Metropolitan Statistical Area. The Allenspark post office has the ZIP code 80510. At the United States Census 2020, the population of the Allenspark CDP was 568. Allenspark is a park in the geographical sense—it is a high meadow surrounded by mountains.