Poll workers will ask to see some form of I.D. Accepted forms are an Iowa Driver's License, new state voter card, military identification and several other types.
Primary elections also happened in Alabama, California, Mississippi, Montana, New Jersey and New Mexico.
The top two finishers in Tuesday's election will square off in November, regardless of which party they are from.
The "blue wave" Democrats hoped would sweep the nation this year, starting in California, was at risk late Tuesday in the state's unusual top-two primary, with early returns showing Republicans threatening to shut out Democrats from appearing on the ballot in at least two congressional contests in November.
Primaries in Alabama include a contest for Republican Gov. Kay Ivey, who's seeking a full term after replacing Robert Bentley previous year.
Renewables and gas sectors slam proposed USA coal-plant bailout
The memo added that "federal action is necessary to stop the further premature retirements of fuel-secure generation capacity". Under a 2010 agreement, Portland General Electric plans to shut Oregon's only coal-fired power plant in Boardman in 2020.
Efforts to recall Democratic state Sen.
Because so many energized Democrats are running for office in California this year, in some races they may collectively carve up the Democratic base into such tiny chunks that no Democratic candidate's chunk will be larger than those of the top two Republican vote-getters.
Recognising the high stakes, Trump sought to energise his supporters in a series of tweets praising his preferred California Republican candidates.
Trump tweeted Tuesday: "In High Tax, High Crime California, be sure to get out and vote for Republican John Cox for Governor".
In the 11th District, Republican U.S. Rep. Rodney Frelinghuysen's decision to retire after 12 terms set up five-way Democratic and Republican primaries. While Republican Diane Harkey held a lead with 25 percent of the total vote, she was trailed by a trio of Democrats who had support in the teens - Mike Levin, Sara Jacobs and Doug Applegate - before the next-closest Republican, who was in the high single digits. There are about 83,500 more independent voters registered in the state than there are Republicans.
There also were contested Democratic primaries for three of Iowa's four U.S. House seats. Democrats need a good day in California to have much hope of seizing the House majority this fall.
£437m Samuel Umtiti release clause ends Jose Mourinho interest
The France centre-back fuelled the speculation in March when he refused to comment on reports he could sign for United. The details surrounding his new buyout clause and total wages should become clear when he puts pen to paper on Monday.
In New Jersey's 2nd District, which covers all or parts of eight counties and includes Atlantic City, Democrats and Republicans were vying to succeed retiring Republican U.S. Rep.
In TV ads, Bright has accused Roby of turning her back on the president.
Menendez has promoted himself as a check on Trump, who lost to Democrat Hillary Clinton in New Jersey in the presidential election. Will it make a difference?
Governor's races will also take shape Tuesday in Alabama, Iowa, South Dakota and New Mexico, where Republicans in most cases are fighting to demonstrate their loyalty to Trump and Democrats are toeing the line, particularly in more conservative states. She held a strong lead over fellow Republican Bruce Whitaker, who was in second. Nate Boulton before he dropped out of the race amid sexual misconduct allegations.
Media from across the country have tuned in to the race, especially since Denham in recent weeks began bucking his own party leadership in an unsual move to force a House vote on immigration policy.
"While disgraced Senator Bob Menendez was accepting bribes in Washington, Bob Hugin was creating jobs for New Jerseyans", National Republican Senate Committee Executive Director Chris Hansen said in a statement.
'Wonder Woman 2': Geoff Johns Teases "WW84"
DC Entertainment CCO and director Patty Jenkins have both teased what appears to be a logo for the planned Wonder Woman 2 . This also means that the sequel will take place around 60 years after the original, which was set during World War 1.
Democrat Bob Lambert, 62, of Fresno, voiced scorn for Republican candidates.