Abstract We studied movement patterns, activity, and home range of the eastern spiny softshell turtle (Apalone spinifera) in northern Lake Champlain (Quebec, Canada; Vermont) from 1996 to 1999. This turtle population is at the northern limit of its range and considered threatened. Of the 30 individuals captured and marked, 15 females and eight males were equipped with radio-transmitters and monitored from two weeks to 29 months. Mean annual home range size for females (32.06 km2, N = 11) was significantly larger than for males (2.75 km2, N = 4). Home ranges generally consisted of a spring-summer concentration area (0.90 km2) and a fall-winter concentration area (1.80 km2), plus the area traversed between these concentration areas. In general, movements did not vary significantly from May to September, but turtles were less active after mid-September. Three hibernacula and three nesting sites were identified. Seventy five percent of the radio-tracked individuals were concentrated in a small area surroundin...