Updated April 17 with added regional hosts.
#-indicates a regional host

Benedictine Supersectional

Timothy Sectional (15 teams)

Sub-sectional A
Aurora Central
#-Hope
Lisle
Montini
Phoenix Military
#-Rosary
Timothy
Westmont

Sub-sectional B
Air Force
#Cristo Rey
Garcia
Intrinsic Downtown
Our Lady of Tepeyac
#-Soto
Wolcott

Hinckley-Big Rock Sectional (18 teams)

Sub-sectional A
Alleman
DePue (co-op)
Genoa-Kingston
Hinckley-Big Rock (co-op)
#-Indian Creek
Marengo
#-Mendota
Oregon
Princeton

Sub-sectional B
#-Byron
Galena (co-op)
North Boone
Rockford Christian
Rockford Christian Life (co-op)
Rockford Lutheran
South Beloit
#-Stillman Valley
Winnebago

Columbia Supersectional

Columbia Sectional (17 teams)
 

Sub-sectional A
Althoff
Breese Central
East Alton-Wood River
#-Father McGivney
Maryville Christian
Mater Dei
Metro-East Lutheran
#-Roxana
Salem

Sub-sectional B
Columbia
DuQuoin
#-Freeburg
Gibault
Massac County
Mt. Carmel
#-Murphysboro
Pinckneyville

Riverton Sectional (17 teams)

Sub-sectional A
#-Marquette (Alton)
Carlinville (co-op)
Gillespie
#-Greenville
Hillsboro
Litchfield
Pana
Southwestern
Staunton (co-op)

Sub-sectional B
Auburn
Beardstown
Pleasant Plains (co-op)
North Mac (co-op)
Notre Dame (Quincy)
Riverton (co-op)
#-Sacred Heart-Griffin
Springfield Lutheran (co-op)
 

Concordia Chicago Supersectional

IC Catholic Prep Sectional (16 teams)

Sub-sectional A
Clemente
Golder
Holy Trinity
Josephinum
Latin
#-Marine Leadership
Noble Street
#-Parker
Rauner

Sub-sectional B
Chicago Academy
#-DePaul
Disney II
#-IC Catholic Prep
Intrinsic
Lycée Français
Rickover Naval
 

Richmond-Burton Sectional (18 teams)

Sub-sectional A
#-Cristo Rey St. Martin
Elgin Academy
Harvest
Johnsburg
Marian Central
Richmond-Burton
Schaumburg Christian
St. Edward
Westminster
One regional host TBA

Sub-sectional B
Chicago Math and Science
Christian Heritage
Ida Crown
#-North Shore Country Day
Regina Dominican
#-Rochelle Zell
Sullivan
Willows
Woodlands

TBA Supersectional

Manteno Sectional (16 teams)

Sub-sectional A
Carver Military
#-Chicago Christian
#-Chicago (University)
Gage Park
Maria
Morgan Park Academy
St. Francis de Sales
Southwest Chicago
 

Sub-Sectional B
Beecher
Bishop McNamara
Coal City
#-Herscher
#-Manteno
Peotone
Reed-Custer (co-op)
Wilmington

Williamsville Sectional (17 teams)

Sub-sectional A
Bloomington Central
Canton
Cornerstone 
Illinois Valley Central
Macomb
#-Monmouth-Roseville
#-Normal (University)
Peoria Christian
Olympia

Sub-sectional B
Athens (co-op)
Decatur Lutheran (co-op)
Monticello
St. Teresa
St. Thomas More
Urbana (University)
#-Warrensburg-Latham (co-op)
#-Williamsville