Tsin Kletsin or Tsin Kletzin is an Ancestral Puebloan great house and archaeological site located on top of South Mesa in Chaco Culture National Historical Park, northwestern New Mexico, United States.
Originally it contained 81 rooms, 3 kivas and a plaza constructed to create a 2-story structure.
The masonry style of this complex is called McElmo (Chaco-McElmo), characterized by large sandstone blocks and some tubular slabs.
However, massive amounts of silt accumulated during flash floods would have forced the residents to regularly (10–15 years) rebuild the dam and dredge the drainage channel, and perhaps as early as every 2 years the water might have overflowed the dam causing some flooding.
Tsin Kletsin is accessible through the South Mesa Trail, 2.6 mi (4.2 km) round trip starting at Casa Rinconada; however, tourists typically do not visit there.