Gov. Pat Quinn signed the historic civil unions legislation into law in January, making Illinois the seventh state, along with the District of Columbia, to give same-sex couples significant legal protections. They include the power to decide medical care for an ailing partner, the right to inherit a partner's property, get full hospital visitation rights and be considered next of kin.

Couples were expected to line up starting at 6 a.m. today outside the Daley Center in downtown Chicago, waiting to get their licenses, said Courtney Greve, a spokeswoman for Cook County Clerk David Orr.

Bernard Cherkasov, the CEO of Equality Illinois, the state's largest gay advocacy group, expects at least 30 couples to take part in public commitment ceremonies Thursday at Chicago's Millennium Park. Quinn also will be on hand.