Who is on the US Silver dollar?

All true (i.e. 90% silver) US silver dollars minted for circulation up to 1935 carry various pictures of Miss Liberty.

Modern $1 coins are sometimes called "silver" dollars out of custom but they don't have any silver. They were made of copper-nickel up till 1999. Since 2000 they've been struck in manganese-brass.

1971-78: President and General Dwight Eisenhower.

1979-81 and 1999: Women's rights advocate Susan B. Anthony

2000-present: Native American Sacajawea

2007-present: Each US president, in order of service.