Washington DC has the highest percentage of female couples at 1.38% though since DC is just a city, that only translates to 985 reported couples. California is 7th in density (0.65%), though first by about double in population.
The places with the most women couples are California (42,000), New York (21,000), Texas (21,000), Florida (18,000), Illinois (10,000), Pennsylvania (10,000)
The California regional breakdown (by "incorporated area") is also interesting, Berkeley has the highest percentage of "lesbian" couples. (3%). Pasadena was actually listed with 136 couples and 0.7% of the total couples were lesbian.
One of the gayest places is some place called Guerneville, 16.8% of the couples are gay. (5.6% are lesbian)
Perhaps I should go visit Berkeley