Interesting - I had never researched the Class A tournament back in those days. South High Fieldhouse opened in December 1940. I'm not sure if there was another venue in Youngstown that could have hosted. The old Rayen gym seems like it would have been too small. The Mahoning County Class B tournament was played at Boardman until South Fieldhouse opened.
From looking at the 1957 version of the OHSAA record book, it looks like they went to the regional format for Class A in 1942 and Class B in 1943.
South High Fieldhouse appears to have hosted 11 regionals - with quite the Stark County representation in those games.
1942 Class A - Canton Lehman beat Warren Harding in final
1944 Class A - Canton Lehman beat Canton Timken
1944 Class B - Akron Ellet beat Bellaire St John
1948 Class A - Canton South beat Canton McKinley
1948 Class B - North Canton beat Midvale
1949 Class A - Niles beat Struthers
1950 Class A - Garfield Heights beat Youngstown Rayen
1950 Class B - Geneva beat Norton
1951 Class A - Canton McKinley beat Martins Ferry
1953 Class A - Girard beat Canton Timken
1954 Class B - Copley beat Columbiana
My apologies to Blue Jay Fan as we've kind of hijacked this thread for a Mahoning Valley history discussion