Kirtland is a city in Lake County, Ohio, United States. The population was 6,866 at the 2010 census. Kirtland is famous for being the early headquarters of the Latter Day Saints movement from 1831–1837 and is the site of the first Mormon temple, the Kirtland Temple, completed in 1836. The city is also the location for many parks in the Lake Metroparks system, most notably the Holden Arboretum.