DAYTON, Ohio  Senator John McCain astonished the political world on Friday by naming Sarah Palin, a little-known governor of Alaska and self-described “hockey mom” with almost no foreign policy experience, as his running mate on the Republican presidential ticket.

Ms. Palin, 44, a social conservative, former union member and mother of five who has been governor for two years, was on none of the widely discussed McCain campaign short lists for vice president. In selecting her, Mr. McCain reached far outside the Washington Beltway in an election year in which the Democratic presidential candidate, Senator Barack Obama, is running on a platform of change.

“She’s not from these parts, and she’s not from Washington, but when you get to know her, you’re going to be as impressed as I am,” Mr. McCain told a midday rally of 15,000 people in a basketball arena here shortly before Ms. Palin, with her husband and four of her children, strode out onto the stage.

Within moments, Ms. Palin made an explicit appeal to the disappointed supporters of Senator Hillary Rodham Clinton by praising not only Mrs. Clinton but also another woman who has been on a major presidential ticket, Geraldine A. Ferraro, Walter F. Mondale’s Democratic running mate in 1984.