Think you have a high income? That's relative, as a place's cost of living can eat away at even the highest salary (consider New York or San Francisco). Financial website SmartAsset recently dug into the data for Texas counties, determining which land in that sweet spot of affordable cost of living and healthy median income.

To do this, the site calculated two different cost of living metrics for a household with one adult and no dependents. One reflected the baseline cost of living in each location, and the other was based on expenditures typical to someone making the county's median income.

Then those two numbers were combined using a weighted average based on how close each county's median income was to the minimum livable income in that area. At that point, income taxes paid in the area were subtracted.

Finally, SmartAsset calculated purchasing power by determining the weighted cost of living as a percentage of median income. The top locations were those with the highest median income relative to the cost of living.

And highest in Texas is — drumroll, please — Fort Bend, slightly southwest of Houston and home of Sugar Land. It barely squeaks out the No. 1 spot with an index of 67.42, derived from a $44,752 cost of living and $93,645 median income.

Coming in hot with an index of 67.08 is Rockwall, a suburb about 20 miles northeast of Dallas that sits on the shores of Lake Ray Hubbard. There, a $93,269 median income easily finances a $44,539 cost of living.

Two more Dallas-adjacent counties are also on the list, with Collin (home of Plano) third and Denton (where the University of North Texas is based) fifth. The former enjoys a $44,111 cost of living on a median $90,124 salary, while the latter earns a median $80,290 a year and lives on $42,487.

One Austin neighbor shows up in the top 10: Williamson County, home to Round Rock and Georgetown, appears at No. 7. The $43,574 cost of living is easily obtainable on a median $79,123 salary.

The Hill Country county of Kendall, which sits southwest of Austin and north of San Antonio, ranks fourth with a $81,023 median salary and $42,969 yearly cost of living.

Brazoria, near the reservoir of the same name and on the banks of the Brazos River, is ninth with a $42,792 cost of living and $76,426 median salary.

West Texas is home to three counties on this list, with Roberts (near Amarillo) at No. 6; Borden County, south of Lubbock, at No. 8, and Midland at No. 10 with an index of 51.26.