The U.S. Census Bureau released 2017 estimates for numerous demographics for select, larger counties and metros in the US.
Within the Rural Capital Area, data is available for Bastrop, Hays, and Williamson counties as well as the Austin metro. This data can be found here:
For smaller geographies, the Census releases 5-year averages. Data for 2017 will soon be loaded into Headlight. All counties and geographies have this data, which can be found here:
Summary tables of Census data can be found in the "Subject Tables" page here: