The properties are distributed across Harris County. There is a concentration in "Downtown Houston", defined as the area enclosed by Interstate 10, Interstate 45, and Interstate 69. More than 100 are in the "Houston Heights" neighborhood whose borders are, approximately, Highway I-10 on the South, I-610 on the North, 45 on the East and Durham on the West. The "inner Harris County" area is defined as the rest of the area within the Interstate 610 loop; "outer Harris County" is defined as the rest of Harris County. There are no listings at all in a few of Houston's exclaves, which extend even beyond the Harris County borders.