How do I search for a half sister when I have limited information

[groom]

From what KOSearch told me she believes it to be:  DC area (Northern Virginia or Washington, DC).

[KOSearch]

I believe she was born anywhere between 1973 - 1976.  I know that's a range but unfortunately, none of us had specifics.

[shellyesq]

I would try checking sites like www.switchboard.com or www.whitepages.com with her first name & your father's surname to see if any possibilities pop up. 

You could also try the US public records index.  A partial database of this is here - https://familysearch.org/search/collection/2199956  Ancestry.com has a more complete version of this database - it is a subscription site, but some public libraries will provide free access. 

I would also try Googling her name or your father's name or checking any newspaper database from the relevant time frame.  It's possible that they could be mentioned in a marriage announcement, obituary, legal notice, etc. 

[KOSearch]

Thank you for your suggestions.