Want to know the racial mix around your congregation? Check out Mapping America: Every City, Every Block, an interactive map produced by the New York Times. The level of geographic detail is astounding, down below census tracts to streets and blocks. Unfortunately, since the data comes from the U.S. Census, the five racial categories are very broad: white, black, Hispanic, Asian, other (the census does take more detailed racial information, but does not provide that level of detail with geographic location).
I looked up the neighborhood immediately around the Unitarian Universalist Church of Palo Alto, and found it is 59% white, 1% black, 5% Hispanic, 32% Asian, and 2% other; I’d estimate that the racial makeup of our congregation is probably 80% white, 1% black, 1% Hispanic, 17% Asian, and 1% other; I suspect those who actually show up on Sunday morning are probably somewhat more racially diverse. (The neighborhood where we live turns out to be only 12% white, which helps explain why my church feels so white when it’s actually more diverse than most of the Unitarian Universalist congregations I’ve been part of.)
Mind you, there are problems with this map. I looked up our old neighborhood in New Bedford, and the map shows people living on the hurricane barrier at the mouth of New Bedford harbor, which is absurd. The underlying data are probably fairly good, but the graphical presentation should not be construed as showing the exact location where people live.