We examined Cassin's sparrow (Aimophila cassinii) territory characteristics in shrub-grassland in northwestern Oklahoma during the 2008 breeding season. We estimated Cassin's sparrow territory area using territory mapping and song playback. Additionally, we determined vegetation cover, and aspect within territories and at nonterritorial sites, at both small scale (214 ha) and large scale (4856 ha). Mean territory size was 0.55 ha. Territories were 1.8 × more likely to be on north aspects than expected. Additionally, territories had greater shrub [sand sagebrush (Artemisia filifolia)] cover than the surrounding landscape.