The map must be redrawn due to shifts in population in wake of the 2010 census. It's a pivotal process that can political power shifts in each district.
The first group of witnesses was Asian American. Among their concerns is that residents of Chicago's Chinatown neighborhood are represented by any of four different Illinois House members and three different state senators.
In drawing the new legislative boundaries, lawmakers must avoid dividing minorities under the new Illinois voting rights act. It sponsor, Senator Kwame Raoul, says the general assembly should reflect the diversity of Illinois.
"Our state should look in a manner where we're respecting of one man, one vote. So equaling the population, try to be contiguous and compact," said Raoul.
With majorities in the state Senate and House and one of their own as governor, Democrats will control the redistricting process for congressional as well as state offices.
Because of Illinois' slower growth, the state will lose one of its 19 seats in Congress, certainly one of those currently held by a Republican.
"Who that's gonna be, partly decided by this map process but you know the voters in the end are the ones who decide who goes to Washington," said Sen. Matt Murphy, (R) Palatine.
Map-makers must also consider the census finding that Hispanics are the fastest growing group in Illinois with enough raw numbers to perhaps warrant a second Latino- majority Congressional district.
"There is no doubt, you can't deny that the growth is there. It's just trying to figure out how we can put that district together," said Lisa Hernandez, (D) Cicero.
And with Chicago's African-American population in decline, some of the majority black legislative districts in the city are likely to disappear.
"For me to sit here as one individual and tell you what may be at the end of this process would be just me looking into a crystal ball and guessing," said Raoul.
Senator Raoul says the Senate will convene 10 to 15 such hearings around the state in an effort to make the 2011 process more transparent. But it's anybody's guess how much the Democratic Party leaders will consider public input when they draw the new map later this year.