began developing the park in the 1870s, molding a flatprairie landscape into a "pleasure ground" with horse trails and a pair of lagoons. Originally named "North Park", it opened to the public in 1877, but landscape architects such as Jens Jensen made significant additions to the park over the next few decades. Between 1905 and 1920, Jensen connected the two lagoons with a river, planted a rose garden, and built a fieldhouse, boathouse, and music pavilion. In 2018, the and partnered with to improve the Jens Jensen Formal Garden. They rehabilitated the natural landscape and repaired deteriorating infrastructure, winning the 2018 Jens Jensen Award from the of the American Society of Landscape Architects. The park played a prominent role in the past for Chicago's Polish community. The Polish Constitution Day Parade once traditionally terminated here at the Tadeusz Kosciuszko statue that was located here before it was moved to Solidarity Promenade on the lakefront Museum Campus in 1981. Additionally, pianist and Polish statesman Ignace Paderewski delivered a famous address where he rallied Chicagoans to the cause of a free and independent Poland. From 2012 to 2014, Humboldt Park was the home of the punk rock–based music festival Riot Fest and Carnival. For 2015, the three-day music festival was met with opposition from Alderman Roberto Maldonado and local residents over the condition of the grass, lack of accessibility during and after the festival, and gentrification of the surrounding area. This led to the festival's relocation south to Douglas Park. In 2019, an alligator was found at the park's lagoon, capturing much interest and media attention.
The stable and receptory is a single building. It was built in 1895–1896 as a half-timbered German country house that combined Queen Anne revival features. The eclectic architecture also incorporated some neo-medieval and neo-romanesque details, like turrets and a Richardsonian courtyard porte-cochere. The Receptory was the visitor center and main building of the park. It included the park superintendant's office, first occupied by Jens Jensen. Visitors would park their carriages there. The rear portion of the building was the stable, with stalls for 16 horses. It is less ornate, but still features many roof dormers and a spire.
Near the boathouse stands a ten-foot-tall monument of the park's namesake, Alexander von Humboldt. Sculpted by Felix Gorling and donated by Francis Dewes, the statue encompasses a globe, a twig in his right hand, a lizard atop a manuscript, and plants at his feet. These inclusions were to symbolize Humboldt's travels and role in establishing geophysics and physical geography sciences.
The German American residents of Chicago commissioned to have a monument created of Fritz Reuter, a German novelist and political martyr. The German American sculptor for this monument, Franz Engelsman had also originally created four relief plaques depicting Reuter's achievements that were placed at the base of the sculpture. However, they were stolen in the 1930s and never salvaged.
Additionally, the park was once home to a statue of Tadeusz Kosciuszko by Kazimierz Chodzinski that was built thanks to funds raised by Chicago's Polish community and moved in 1981 to the city's lakefront.
