Until the late 1800s, looking down from atop Cedar Hill you would have seen little more than a countryside landscape divided by an unkempt dirt road. The hillside known as Cedar Glen hosted few travellers aside from farm wagons and, later, visitors to the springs resort at the foot of the hill. In less than a century, this scene would be replaced by one of a busy, six-lane road as Cedar Glen became the biggest gateway to the Heights from the city of Cleveland.
One of Cedar Glen's most salient characteristics is its gradual rise in elevation. The western edge of the Portage Escarpment causes this natural formation. The Portage Escarpment not only divides the Allegheny Plateau and the Great Lakes Basin, but also acts as a boundary between Cleveland and its suburban "Heights" to the east. Originally the eastern part of Cedar Glen and the high ground to which it leads belonged to East Cleveland Township. When Cleveland Heights incorporated as a village in 1903, it engulfed the southern part of East Cleveland Township, which included farmland and Cedar Glen.
Another natural feature that, for a time, made Cedar Glen a well-known area was Doan Brook, which was piped and buried underground in 1929. In the early 1800s, bluish grey sandstone called Euclid bluestone was quarried along the brook. The hard sandstone was used for everything from laundry tubs to sidewalks. Later in the century Doan Brook again brought attention to Cedar Glen. Dr. Nathan Hardy Ambler was a former dentist and the owner of the Cedar Glen property through which Doan Brook passes on its way from Shaker Lakes to Lake Erie. Although the blue-green water tasted like sulfur, Ambler began bottling and selling it to local restaurants. Because patrons believed the water offered health benefits and hydrotherapy was becoming a popular treatment method, Ambler and his partner Daniel O. Caswell opened the Blue Rock Spring House in Cedar Glen. The water resort and sanitarium operated from 1880 until 1908 when popularity began to fade.
Cedar Glen began its transition to one of Cleveland's most important transportation gateways from the suburbs in 1896 when entrepreneur and suburban developer Patrick Calhoun donated a large tract of land to the city's park system. One of the conditions of the gift was that Calhoun would be permitted to run a double-line street railway through Cedar Glen. Construction began that fall on the street railway that was intended to bring passengers to and from Euclid Heights and Ambler Heights, prestigious residential allotments on the "Overlook." The increase in suburban residents and visitors made possible the construction of the Cedar Fairmount retail district at the top of the hill.
By the 1920s Cedar Glen was bustling with heavy streetcar and automobile traffic. At the end of that decade a tunnel and platform were built on the western end of Cedar Glen in conjunction with the construction of the Cleveland Union Terminal, further connecting Cleveland Heights to its urban neighbor. In the mid 1950s Cleveland Transit Service (CTS), the predecessor of today's RTA, built the University Circle Rapid Transit Station at the same location on the bottom of Cedar Glen where the tunnel was constructed twenty-five years earlier. Completely transformed from its onetime status as a barren, dirt road, Cedar Glen now remains a well-traveled gateway to and from Cleveland.