By 1930, Burrill Avenue ran through the heart of campus, stretching from Gregory Drive to a street which no longer exists, but which once ran east-west immediately south of the modern Grainger Library (the parking lot between Talbot and the clay tennis courts was once part of this road). 
It ran directly North from Gregory Drive on a line drawn south from the point midway between the modern Gregory Hall and Foellinger Auditorium. At the west-east line that draws the southern border of the Observatory, it began a curve to the east to run between Foellinger and Smith Music Hall, forming a parking area along the east of the front lobby of Foellinger. It then ran directly north through the Main Quad, until it reached immediately south of Harker Hall, where it then curved to the west to run in front of University Hall, where it formed a circular drive. It then intersected with Green Street, before continuing directly north into engineering campus. A circular driveway connected it to the Health Service building (where Everitt is today) on the west, before it continued on to deadend on to Springfield Avenue. 
By 1939, with the demolition of University Hall and the construction of the Illini Union, Burrill Avenue no longer ran through the Main Quad. Its southern portion ended at the Auditorium and its northern section now began at Green Street. Two roads now ran through engineering campus, with the new road running north-south between modern Engineering Hall and MSEB from just shy of Springfield Avenue down to a side parking lot beside the Illini Union on its east side.