First, there were her parents who were killed in the metroid shower.

Then her aunt adopted her and was her family. But when Auntie Nell went to Metropolis with her fiance, Lana didn't come along and had to find somewhere else to crash.

This brings us to family number 3, the Sullivans, who under Chloe's good will let Lana move in with them in their house so she wouldn't have to leave Smallville.

Of course looming in the background was her real biological father, Henry Small. A lawyer who had a fling with Lana's mom when Lana's parents were seperated. It seems though, that her relationship with Henry Small took a back seat as he had to try and get his own family back on track.