Many voters were fuming late Tuesday because of long lines at the polls.
According to the Harris County Clerk's Office, there were 68 Republican and 78 Democratic polling locations throughout the county.
About 7 p.m., many voters reported being in line with dozens of others waiting to cast their ballots.
"We were totally taken by surprise," voter Cindy Hebert said. "If we thought it was going to be that long, we probably would have came a little earlier in the day."
"It's frustrating to wait that long, but it's an important process," voter Matt Morris said. "I'm proud of people for hanging in there, sticking with it to put the vote in."
Anyone who was in line at 7 p.m. was allowed to vote.
Officials at the polling location on West Gray said the last person there cast their ballot about 9:30 p.m.
County officials said they were working to figure out why the lines at some locations were so long.