Wooden beams and planks from the Spanish Colonial church and other structures in Las Trampas, north-central New Mexico, have been sampled and dated by dendrochronology. Dates of AD 1735 imply Spanish occupation of the area 16 years prior to official grant. Stockpiling of timber for church construction began as early as 1758. Exterior walls were 15 feet high by 1762 and were completed to roof level by 1764. Late in 1776, wood was cut for a dust-guard over the adobe altar and mural. According to clustering of tree-ring dates, a new altar and wooden altar screen were constructed soon after 1785. Beam re-use was prevalent. Timbers bearing early dates were incorporated into the 1785 altar screen, indicating re-use from within the church or from other pre-1760 structures. A roof viga was later used as a floor plank after reroofing. In domestic buildings, re-use of beams is repeated. Replacement of beams supporting the balcony was made in the 1860's and 1870's. Tree-ring dates indicate repairs again in the 1930's and 1943. A survey of the literature pertaining to dendrochronology of historical sites revealed that shaping of beams and lack of thorough sampling have heretofore hindered successful application. The documentary record of Las Trampas art and architectural history has been further refined by tree -ring dating, and the study reaffirms the potentials for historical sites dendrochronology.