At least 14 women won municipal council seats in Saturday's poll far exceeding expectations in the ultra-conservative kingdom.
"The participation of women represents an important step forward in Saudi Arabia toward a more inclusive electoral process that will ensure all citizens are represented in a government accountable to all Saudi citizens" State Department spokesman John Kirby said in a statement.

"As we have long said the inclusion of all citizens in voting and governance is critical to the prosperity stability and peace of all nations and we welcome this historic milestone."
More than 900 women were among the 6440 candidates standing for seats on 284 councils.
However they had to overcome a number of obstacles to participate.
Female candidates could not meet face-to-face with male voters during campaigning while neither men nor women could publish their pictures.
Women voters said registration was hindered by factors including bureaucratic obstacles and a lack of transportation.
As a result women accounted for less than 10 percent of registered voters.
Saudi Arabia is an absolute monarchy with some of the world's tightest restrictions on women including a ban on driving.
It was the last country to allow only men to vote and polling stations were segregated.