CHICAGO (AP) _ Gay and lesbian couples across Illinois can now legally wed as the state's law allowing same-sex marriage took effect Sunday.

June 1 marked the first day all of Illinois' 102 counties could begin issuing marriage licenses to same-sex couples after a piecemeal start where some county officials began granting licenses months ago following a federal court ruling.

Gay couples and civil rights advocates across the state are planning to mark the date with blessing ceremonies and group weddings, and several county clerks are opening briefly to issue licenses for those who don't want to wait for Monday morning.

``June 1 will be a history-making day in Illinois,'' said Bernard Cherkasov, CEO of the gay rights group Equality Illinois. ``At long last, the state will recognize their families for what they are: which is equal in love, equal in commitment and equal in marriages.''

Macon County Clerk Stephen Bean said he plans to be in his Decatur office Sunday to issue the licenses. His office opened at midnight when Illinois began issuing civil unions in 2011 and was among the 16 or so that began issuing marriage licenses earlier this year ahead of the June 1 rollout.

``I had made a commitment to several of the couples who'd gotten civil unions to be open,'' he said. ``We have some couples that wanted to wait until the first official day, so I'm going to come in for a couple of hours.''

In Sangamon County, the clerk's office began issuing licenses Friday for the first time so couples could wed Sunday. Kelley Bergae, the director of the county's vital records, said 11 same-sex licenses were issued _ 8 converting their civil unions to a marriage and 3 getting a marriage license.

``They're all pretty excited,'' she said.

Gov. Pat Quinn signed the state's gay marriage law in November, but last February, a federal court ruling in Chicago declared Illinois' original ban unconstitutional, clearing the way for some same-sex couples to marry.

Equality Illinois officials estimate about 1,300 couples have wed since then, most of them in Chicago's Cook County.

Most of the state's remaining 86 counties opted to wait until the Religious Freedom and Marriage Fairness Act officially takes effect, in some cases worried that issuing licenses before June 1 could trigger lawsuits against the counties and perhaps cause legal problems for the couples themselves.