Hillary Clinton made history Tuesday night when she became the first woman nominated by a major political party to be president of the United States.

While she may have put "the biggest crack" in the glass ceiling in U.S. politics, women remain significantly under-represented in local, state and federal offices.

A Rutgers University Center for American Women in Politics study found that women make up less than 20 percent of Congress. Only one in four state legislators are women and there are only six female governors.

Elizabeth Maurer, director of programs at the National Women’s History Museum, said Clinton's accomplishment is a historical milestone but getting more women in elected office begins with outreach.

"The Senate now has the most number of women they’ve ever had," Maurer said. "Maybe with Hillary Clinton becoming party nominee it will encourage more women to run for office."

The Rutgers study also found that women are underrepresented in local offices.

Nineteen of the 100 largest cities have women mayors, and less than 19 percent of cities with over 30,000 people are led by women.

Maurer said historically, women enter the political world based on issues over ideology.

"As more women go into politics and they rack up more accomplishments or more qualifications or their resumes grow lengthier, than you’ll see more women becoming more competitive in these different offices," Maurer said.

Twenty-three state have never elected a woman governor.

Mississippi, Vermont and Delaware are the only three states to never send a woman to the U.S. House or Senate.