There doesn't appear to be anything in the census itself to identify locations in the 1840 census of Tishomingo, other than that those persons (including your Wades) on page 231 were in the "Northern district" of the county. Along the left-hand side of the page, only the county is identified. It is possible that there is somewhere a document detailing what divisions were alloted to the various census takers, but I wouldn't know where it might be. You might try quering someone with the USGenWeb Census Project. Otherwise, land records are your best bet, and definitely worth checking if you can get to Tishomingo County and your ancestors were land owners. Margaret Lindsey Smith, who will finally get to Tishomingo County next week to locate records on her Lindsey ancestors!