Located in the southeastern corner of Chuuk State, and forming part of the tight cluster of three atolls that comprise the Lower Mortlock Islands group, is the large atoll of Satawan — the most southerly component of Chuuk state. Off the northeast-facing side of Satawan lie the small atolls of Etal and Lukunor, 6 km and 8 km distant, respectively; Chuuk lies 250 km to the northwest.

Satawan forms a large, rectangular-shaped structure of over 400 km² in area with dimensions of 32 km by 13 km; its longest axis is orientated from northwest to southeast. With the exception of three large passes (one on the south and two in the north) the rim of the atoll is continuous, forming a narrow barrier between the open ocean and the deep central lagoon.

The atoll rim is topped by many small islets — usually quoted at between 30 and 90 in number — with a combined land area of 4.59 km². The largest islands are the highly elongate Ta (1.55 km—) and the island of Satawan (1.1 km²), which together line much of the southeastern rim. Vegetation on the islands predominantly consists of coconut palm (Cocos nucifera) and breadfruit (Artocarpus altilis).

image: earth sciences and image analysis laboratory, nasa johnson space center