Michael Parent, left, gets instructions on submitting his ballots from warden Denise Shames while voting Tuesday, Nov. 7, 2017, in Portland. (AP Photo/Robert F. Bukaty)

Mainers are heading to the polls Tuesday to decide whether Maine expands Medicaid health coverage to an estimated 70,000 residents and whether the state should allow an international businessman to build a new casino in York County.

Voters in Lewiston and Auburn are deciding whether to merge their cities and to choose the mayors in those two cities.

And around the state, voters will decide on local ballot questions and races for town councils, select boards and school boards.

Most polling places in Maine open at 7 or 8 a.m., but times vary by community. All Maine polls close at 8 p.m.

• Polling places and times for residents of Franklin, Oxford counties and nearby towns
• Polling places and times for residents of Androscoggin County and nearby towns

It’s still not too late to register to vote. Mainers who are 18 or older can register at polling places on Election Day.

Results of the state and local elections, as well as elections of note in other part of the country, will be updated and posted at SunJournal.com.

Here is a guide to some of the big decisions voters are making.

LEWISTON-AUBURN MERGER

Voters in Lewiston and Auburn are voting whether to merge their two cities, something they have discussed for years. If passed by both cities, the measure would initiate a two-year transition process and lead to a new city starting on Jan. 2, 2020.

Supporters argue it would save money for residents of both cities, and the unified city could attract more young professionals to fill a workforce shortage. Opponents worry about losing a sense of identity and question whether the savings would be as promised.

MAYORS OF LEWISTON AND AUBURN

In Auburn, city residents will choose between Adam Lee and Jason Levesque for mayor.

In Lewiston, city residents will choose among Shane Bouchard, Mark Cayer, Ben Chin, Ronald Potvin and Charles Soule. If none of the candidates receives more than 50 percent of the vote, then a runoff election between the two candidates who get the most votes will be scheduled for December.

CASINO LEADS STATE BALLOT

Question 1 on the state ballot is seeking voter approval for a third casino in Maine, which would be built somewhere in York County.

The referendum is written to allow only one person, Shawn Scott, to apply for a permit to build the casino. Supporters have argued a casino in York County would create more than 2,000 permanent jobs and generate $45 million in annual tax revenue, projections that have been dismissed by critics of gambling as an economic development tool.

The controversial campaign was the subject of a probe by the Maine Ethics Commission for violating state campaign finance laws by failing to disclose the true source of its funds and by missing deadlines to file reports; on Friday, the commission levied $500,000 in fines against the four committees behind the referendum for those violations.

MEDICAID EXPANSION

Expanding eligibility for MaineCare, the state’s Medicaid health insurance program, is Question 2 on the state ballot.

Maine will be the first state in the nation to weigh in on Medicaid expansion by referendum. It is among 19 states whose legislators or governors have not expanded Medicaid under the Affordable Care Act. Republican Gov. Paul LePage has vetoed Medicaid expansion five times, which led to the effort by supporters to put the issue on the ballot.

Supporters of expansion have said it would give health care coverage to about 70,000 low-income Mainers and help struggling rural hospitals gain better financial footing. About 265,000 Mainers currently have Medicaid. Opponents argue that hospitals would benefit at the expense of Maine taxpayers.

BOND ISSUE AND PENSION REFORM

Question 3 on the state ballot seeks approval for a $105 million bond to fund repairs and improvements to the state’s transportation infrastructure. The bulk of the money would be directed to repair priority roads and bridges. Dollars would also be allocated for the state’s sea and air ports, freight and passenger railroads and pedestrian and bicycle infrastructure.

Question 4 is a proposed constitutional amendment dealing with amortization of losses to the state’s pension fund. Currently, the state has 10 years to pay back any unfunded liability that was created by investment losses. Question 4 would increase that timeline to 20 years, which the state says would insulate the system from shifts in the economy.

Megan Doyle of the Portland Press Herald contributed to this report.