托洛洛山美洲际天文台（Cerro Tololo Inter-American Observatory，缩写为CTIO）位于智利首都圣地亚哥以北约600公里的托洛洛山山顶，是美国国家光学天文台（NOAO）的一部分。主要设备是4米口径的布兰科望远镜和4.1米口径的SOAR望远镜，以及属于密歇根大学的施密特望远镜。

托洛洛山海拔2200米，属于安第斯山脉，这里气候干燥，全年有300多天可用于天文观测，是世界上条件最好的天文台台址之一。1967年，美国国家科学基金会（NSF）和大学天文研究协会（AURA）开始在这里投资兴建天文台，1976年建成并开始使用。

The Cerro Tololo Inter-American Observatory (CTIO) is an astronomical observatory located on Cerro Tololo in the Coquimbo Region of northern Chile, with additional facilities located on Cerro Pachón about 10 kilometres (6.2 mi) to the southeast. It is within the Coquimbo Region and approximately 80 kilometres (50 mi) east of La Serena, where support facilities are located. The site was identified by a team of scientists from Chile and the United States in 1959, and it was selected in 1962. Construction began in 1963 and regular astronomical observations commenced in 1965. Construction of large buildings on Cerro Tololo ended with the completion of the Víctor Blanco Telescope in 1974, but smaller facilities have been built since then. Cerro Pachón is still under development, with two large telescopes inaugurated since 2000, and one in the early stages of construction.