The mayors warn a loss in funding would force drastic cuts in public safety and other services.
Mayors fear they may be forced to raise property taxes if lawmakers cut money that is legally owed to towns and cities.
Local officials say their budgets are bare bones. They have already made severe cuts to services and employees.
Faced with a huge budget deficit at the end of a fiscal year, state lawmakers say they are running out of time.
Oak Park police officers have been spared during rounds of village layoffs over the past three years, but that may not be the case if state lawmakers act on a proposal to cut or delay hundreds of millions of dollars legally owed to local communities. For Oak Park, it means losing 10 percent of its operating budget.
"Ten percent means for Oak Park means the possibility of laying off 50-60 people, the possibility of closing a fire hall," said David Pope, Oak Park village President.
Pope was one of dozens of suburban leaders who came together Thursday to protest cuts to local governments.
"There isn't a mayor in this room or across the state that hasn't cut back on personnel, or laid off, or created furloughs," said Palos Hills Mayor Jerry Bennett.
The local officials say they have cut enough, and if they are forced to cut again, property taxes may be raised.
When Illinois passed a state income tax in 1969, local governments were legally guaranteed a portion of the revenue to pay for local services. Mayors say they are trying to stop state lawmakers from changing the law and keeping the money.
"This money was never theirs to be taken away or to be negotiated with," said Lynwood Mayor Eugene Williams.
"Stop the blackmail and extortion. Give us the money that is owed to us," said Eugene Munin, Chicago budget director.
Local officials say it is time for Springfield to tighten their own belts. "I know there are state legislators who continue to use the state airplane to go back and forth to Springfield. There are simple things that can be done," said Tower Lakes Village President Kathleen Leitner.
State lawmakers must come up state budget plan before a May 31 deadline.
"To the extent that any shared sacrifice will be visited on communities and local governments, my hope would be that it would come with reductions in unfunded mandates that the state puts on these municipalities," said State Senator Matt Murphy.
Murphy could not say what specific mandates he would lift for local governments.
Illinois Governor Pat Quinn says he is against the Senate Republican proposal to cut millions for municipalities. However, Quinn does support delaying payments.
Mayors say they can't afford to wait for the money. The mayors say they have seen no evidence of state lawmakers cutting salaries or pensions.