After the Second World War the state took over operation of the park, and expanded its size beyond the original land donated by Harrison: six purchases between 1946 and 1949 increased the park's area from to at a cost of $26,328.
After the Second World War the state took over operation of the park, and regular passenger service ended on the rail line through the gorge. Additional tracts of land expanded the size of the park beyond the original land donated by Harrison: six purchases between 1946 and 1949 increased the acreage from to at a cost of $26,328.