Census Records

Since Terrell County was created in 1905, it's first census is in 1910. For the two censuses before that, folks in the area would have been enumerated in Pecos County. For 1860 and 1870, they would have been part of Presidio County and they would have been in Bexar County for the first US Census for Texas in 1850. Indices and images are available to everyone with a free account at the LDS on-line library. Don't forget to check adjacent counties.
1910 - This is the second census that asked for number of years married, number of children borne by females and number of living children. The index to this census is available to everyone with a free account at the LDS on-line library.
The 1920 census was enumerated in January and many families were missed, likely due to weather. It offers very little in the way of extra information except for the names of the roads on which the people lived. The index to this census is available to everyone with a free account at the LDS on-line library.
The 1930 offers addresses for folks in town, age at first marriage and veteran status. The index to this census is available to everyone with a free account at the LDS on-line library.
The 1940 offers addresses for folks in town, education level, residence in 1935, employment status and total income for 1939. The index to this census is available to everyone with a free account at the LDS on-line library.
The 1950 Federal Census desn't offer as much information as in previous years but is still worth investigating. The index to this census is available to everyone with a free account at the LDS on-line library.