Voters in Cannon Ball, N.D., filled out their ballots for the midterm election on Nov. 6, 2018.Credit...Hilary Swift for The New York Times

North Dakota officials have reached a settlement with two Native American tribes over the state's restrictive voter identification law.

The settlement, announced on Thursday, includes a legally binding consent decree to ensure that Native American voters are not disenfranchised. It is a major victory for the tribes and — pending formal approval by tribal councils — will resolve two lawsuits challenging the constitutionality of the law, which requires voters to show an ID with a residential address.

Many Native American reservations do not use traditional addresses, and the law — which the Republican-controlled North Dakota Legislature passed shortly after a Democrat, Heidi Heitkamp, won a close Senate race in 2012 with strong support from Native Americans — meant they could not vote with an ID that listed a post office box as an address. Ms. Heitkamp was defeated by Kevin Cramer, a Republican, in 2018.

Under the new consent decree, the North Dakota secretary of state will be required to ensure that Native Americans can vote even if they don't have a residential address, or if they have one but don't know what it is. (In many cases, buildings have an official address in county records but no signage, and tribal members have never used the address.)

The decree will be enforced by a federal court order and will require the state to take specific steps to inform voters of the changes and train poll workers.

In this year's elections, Native American voters will be allowed to mark their homes on a map, and it will be the state's responsibility to use that information to verify their official addresses and make sure their ballots are counted. The state will also be required to provide the official addresses to the voters and their tribes, which could then issue tribal identification for use in future elections.

This formalizes an arrangement that some tribes used in the 2018 midterms, when a federal court allowed the voter ID law to take effect less than two months before Election Day. Tribal officials were stationed at polling places on reservations to issue handwritten identification on the spot, using ad hoc addresses, to voters who pointed out their homes on a map.

The secretary of state, Al Jaeger, will also work with the North Dakota Department of Transportation to issue free IDs on every reservation before each statewide election. And he agreed to "work in good faith" to secure funding to reimburse tribal governments up to $5,000 apiece per election for the administrative costs of issuing addresses and IDs.

Mr. Jaeger's office has announced a public hearing on emergency administrative rules to carry out the state's new obligations.