Maud Lee Wise

My grandmother was Maud Lee WISE.  She married Eugene Hairston. 

On the 1910 Leesburg, Loudon County, VA she is on census report, as age 8.  Year of birth would be 1902, although we have always used 1900 while she was living.  Maggie Wise is listed as mother, but the census report for how many children Maggie has listed 0  I don't believe Maggie is the biological mother of Maud or her brothers, Clifton and Richard.  They are all listed as servants in the McKimmey home. 

How do I go about trying to locate birth information.  Leesburg birth records were not recorded then.  Maud and her brothers could easily pass for white. Maggie was very dark skinned.