According to the U.S. Census Bureau, the Coaldale CDP has an area of , all of it land. The CDP extends southwest out of the Arkansas River valley up into San Isabel National Forest and the Sangre de Cristo Range. The southeastern edge of the CDP follows the Hayden Creek valley up to Hayden Pass; the southwestern edge follows the Saguache County line along the crest of the Sangre de Cristos; and the northwestern edge follows Stout Creek and Kerr Gulch Road back down to the Arkansas River valley.