The racial and ethnic makeup of Thurston County has become more diverse with the passing of decades. In 1970, more than 98% of the population of the County was White/Caucasian. By 1990, this number had decreased to roughly 92%.
This number likely decreased further between 1990 and 2000, when 86% of Thurston County's people classified themselves as White only. However, census data from 2000 cannot be directly compared to previous censuses, as 2000 marked the first time that respondents were allowed to choose more than one race to define their racial background.
Comparisons between the 2000 and 2010 data, nevertheless, are appropriate and display the further diversification of the county. As part of Census 2010, the proportion of people that classified themselves as "White alone" fell to 82% of the population. The Asian population comprised 5% of the county residents, and people that classified themselves as being two or more races constituted an additional 5% of the population.
The Hispanic and Latino population in Thurston County, which may include persons of any race, also increased from 2000 to 2010. The Hispanic population grew from less than 5% of the population in 2000 to 7% of the population – totaling 17,787 individuals – in 2010.