Represa del Sisga, Artificial reservoir in Cundinamarca, Colombia.

Represa del Sisga is a concrete gravity dam on the Sisga River in Chocontá, Cundinamarca, 55 km along the Bogotá–Tunja road. The dam rises 52 m from its base to a crest at 2674.5 m above sea level. Upstream it holds the Embalse del Sisga, a lake of 637 ha whose dark blue water reaches back toward low green hills and wooded points of land.

Construction of the Sisga dam began in 1948 and was completed in 1951 by the American firm Raymond Concrete Pile and Wiston Bros Inc., commissioned by the Caja de Crédito Agrario, Industrial y Minero. It was built to regulate the flows of the Sisga River and prevent flooding in Bogotá, and its reservoir also stores water released in the dry season through the Tibitoc plant.

The reservoir's shores host a recreation park created as a tourist point for Cundinamarca, drawing on its proximity to Bogotá. Motor sports, sailing and sport fishing competitions are held there through the year, and the lake's depth allows diving to observe species adapted to the water. Planted forest and pasture surround it.

The reservoir lies 55 km along the main road from Bogotá to Tunja, in the Chocontá municipality. The dam crest stands at 2674.5 m above sea level, and the spillway channel runs 650 m along the right bank. The rainy season lasts from May to October, with a dry spell from December to March.

The reservoir's capacity was revised in 2004 when the CAR re-measured the basin: silting over 53 years of operation had cut the design volume of 101.2 million m³ by 11%, to 94.3 million m³, and the surface from 653 to 637 hectares. Fourteen open-tube piezometers are read daily to monitor seepage in the dam and its abutments.