Chester, last year's district champion, earned the second seed. The Clippers will host No. 31 West Chester Henderson.
Great Valley earned the No. 3 seed and will host Wissahickon. The Patriots will play Wednesday night for the Ches-Mont League championship and have won eight straight games.
In Class AAA, Holy Ghost Prep earned the No. 1 seed and will host Sun Valley, the eighth seed, Saturday.
The Firebirds will open the Bicentennial League playoffs on Wednesday. They have won their last four games.
Seedings for the Class AA and Class A tournaments have yet to be announced.
CLASS AAAA FIRST ROUND
All games start at 7 p.m.
Norristown (32) at Conestoga (1)
Methacton (17) at Ridley (16)
Bishop Shanahan (25) at Penn Wood (8)
Central Bucks East (24) at Lower Merion (9)
Kennett (29) at Spring-Ford (4)
Harriton (20) at Coatesville (13)
Academy Park (28) at Pennsbury (5)
Central Bucks South (21) Oxford (12)
West Chester Henderson (31) at Chester (2)
Souderton (18) at Pennridge (15)
North Penn (26) at Abington (7)
Haverford High (23) at Upper Darby (10)
Wissahickon (30) at Great Valley (3)
Radnor (19) at West Chester Rustin (14)
Down. East (27) at Plymouth-Whitemarsh (6)
Central Bucks West (22) at Penncrest (11)
CLASS AAA FIRST ROUND
Times to be announced.
Sun Valley (8) at Holy Ghost Prep (1)
Glen Mills (5) at Octorara (4)
Upper Moreland (7) at Lower Moreland (2)
Pottsgrove (6) at Pope John Paul II (3)