We radiocollared 45 red tree voles (Arborimus longicaudus) in western Oregon and monitored their movements during July 2002–September 2003. We predicted that home range areas would be larger in young forests than in old forests and that males would have larger home ranges and use more nests than females. We tracked individual voles for 82 ± 9 days (mean ± SE; range = 24–307 days). Voles were active primarily at night, although we did see voles outside their nests during the day on two occasions. Of the 45 voles, 18 (4 males, 14 females) occupied a single nest tree and adjacent foraging trees that had interconnecting branch pathways with the nest tree. The other 27 voles (11 males, 16 females) used ≥2 nest trees (range = 2–6). Average distance between alternate nests use by individuals was 45 ± 5 m (range = 4–162 m). Estimates of mean (± SE) and median home range size were 1,732 ± 366 m² and 760 m², respectively (range = 36–10,308 m²). Little variation in home range size was explained by gender or age of voles, or by forest age. However, females occupied fewer nests and made fewer movements between nest trees than males. Male home ranges were larger than females during late winter and spring during the peak breeding period (2,475 ± 1,076 m² and 790 ± 239 m², respectively). We did not detect use of ground nests by radiocollared voles, but we did document occasional cases where voles moved on the ground between nest trees.