Such fine granularity would be unusual for any app store. In Roku's case you can choose on "country" level, i.e. "United States", "Mexico" et al.
PS. Oh! But wait... you can use
roChannelStore.GetUserRegionData() to check account's ZIP code and then programmatically politely decline to run if not a match.
Sheesh! Sometimes i have a stroke of genius
... but then i promptly recuperate
