A federal judge is allowing same-sex couples to get married in Cook County, starting immediately.

Judge Sharon Johnson Coleman’s ruling, issued this morning, applies only to Cook County, Illinois’ most populous county, which includes the city of Chicago.

Coleman’s written order says couples should not have to wait for a state law, passed last year, to go into effect. The measure passed by the legislature and signed by Democratic Gov. Pat Quinn set June 1 as the date on which same-sex couples could legally marry in Illinois.

Coleman wrote, “Committed gay and lesbian couples have already suffered from the denial of their fundamental right to marry.”

She also quoted Martin Luther King, Jr. writing, “The time is always ripe to do right.”

The American Civil Liberties Union of Illinois and Lambda Legal filed the lawsuit against the Cook County Clerk on behalf of a handful of same-sex couples seeking the right to marry immediately.

County Clerk David Orr was the state officer formally listed as the defendant. But because Orr supports same-sex marriage, there was no opposition to the lawsuit, and he moved promptly to announce and put the order into effect.

“We’re thrilled that Judge Coleman recognized the serious harm to the many Illinois families from continuing to deny them the freedom to marry,” said John Knight, LGBT and AIDS Project Director for the ACLU of Illinois. “The U.S. Constitution guarantees these families the personal and emotional benefits as well as the critical legal protections of marriage now, and we are thankful that the court extended this dignity to couples immediately.”

Couples in Cook County must wait a day after getting a license before they can be married.

Meantime, county clerks in the rest of Illinois are waiting to see if the ruling applies to them as well. Coleman wrote in her ruling, “Although this Court finds that the marriage ban for same-sex couples violates the Fourteenth Amendment’s Equal Protection Clause on its face, this finding can only apply to Cook County based upon the posture of the lawsuit.”

Katherine Schultz — clerk of McHenry County in Chicago’s outer northwest suburbs — said she’s waiting for June 1 to issue marriage licenses until told specifically otherwise.

“Until there is something more definite given to McHenry County, and I would assume other outlying counties, we will go by what the state statute says,” she said.

Schultz said that even if she were ordered to start granting marriage licenses to gay couples, she doesn’t have the right state forms yet.

Tony Arnold covers Illinois politics for WBEZ. Follow him @tonyjarnold.

Alex Keefe covers politics for WBEZ. Follow him @akeefe.