The plot of land that is today "Triangle Park" was formed from Lake Forest's 1857 town plan, created by landscape architect Almerin Hotchkiss. His design for Lake Forest
integrated the town into the terrain, with the area’s natural features of lake,
ravines, bluffs, and groves guiding the street plan. This meant that in place
of traditional city blocks, the curvilinear roadways came together to create
uniquely shaped lots like that of Triangle Park. (The plan, created long before
the advent of the automobile, also did not anticipate the traffic challenges such
irregular intersections could create.)

Triangle Park was the site of Lake Forest's first public building, the Lake Forest Hotel (later "Old Hotel," a sheltering place for prospective early residents as well as the site of meetings and school classes. In 1861, the community's founders met at the hotel and voted to incorporate Lake Forest as a city.

Years later, the hotel had become a run-down boarding house. In the 1890s, the heirs of the property's owner, Henry Pierson, sold it to a group of Lake Forest residents who
banded together to purchase it, and then gave it over to the city. Interestingly,
the Pierson heirs included a stipulation in their sale of the land that
required it to be used for charitable, educational, benevolent or public park
purpose – otherwise it would revert to Lake Forest College. The former Old
Hotel building was then moved to a site on Wisconsin Avenue, where it stood
until its demolition in 1973.

It became a public park and in the 1910s was an improvement project of the Lake Forest Garden Club (then the Garden Club of Illinois). Due to its shape, it became known as Triangle Park, and was home to many
summer picnics, baseball games, Christmas tree lightings, and even a four-ton
fountain donated by Paul Kruger. The Park even had a
pool in the 1920s. Later in that decade, Triangle
Park was considered as a potential location for the Lake Forest Library before
the current location was settled upon and acquired.

Today, Triangle Park is best known for the famous resident, the deer statue. The deer’s home originally was at
the Thomas Byrne residence located at 644 East Deerpath - just two blocks northeast. (The third mayor of Lake Forest, David Lake, originally built the
home in 1860.) Byrne had a landscape gardener who decorated his garden with
many statues, though the deer is the only one that still remains today. The deer was
made in Austria, and commissioned between 1901-1903 to stand in front of the
house because Byrne, an avid sportsman, though there should be a “deer” on
“Deerpath.” For several years after the deer arrived, students from the college
‘deernapped’ it and moved it to campus every Halloween. In 1946, the Byrnes
sold the house to the Earle H. Muzzy family. The Muzzy family donated the deer
to its now resting home in Triangle Park in the 1960s. It is often decorated for holidays and special occasions, even donning a mask during the 2020-2021 coronavirus pandemic.