Gateway Arch National Park ⓘ

Gateway Arch National Park, formerly Jefferson National Expansion Memorial, consists of the Gateway Arch , the museum under the arch , and St. Louis' Old Courthouse . During a nationwide competition in 1947-48, architect Eero Saarinen 's inspired design for a 630-foot stainless steel arch was chosen as a perfect monument to the spirit of the western pioneers. Construction of the Arch began in 1963, and was completed on October 28, 1965, for a total cost of less than $15 million. The Arch has foundations sunk 60 feet into the ground, and is built to withstand earthquakes and high winds. Fees are charged to ride the unique tram system to the top. A Grand Staircase leads from the St. Louis levee to the base of the Gateway Arch. Located just two blocks west of the Arch, the Old Courthouse is one of the oldest buildings in St. Louis. Construction began in 1839. It was here that the first two trials of the Dred Scott case were held in 1847 and 1850. The building reopened after extensive renovations on May 3, 2025. The park collections include books, images, objects and papers about the history of the park, the history of westward expansion, the Lewis and Clark expedition, and St. Louis history. The park's total acreage is 90.96 acres. Learn more about the history of park from our Administrative History , 2010 Cultural Landscape Report , Historic Structure Report for the Old Courthouse , or Historic Structure Report for the Gateway Arch.

Our most widespread plant is ornamental turf grass, shown as green on the above map. The grass is a hardy and fast-growing fescue blend and covers 74 acres. During the height of the growing season, it needs to be mowed once or twice a week. Keeping the lawn looking its best would be a full-time job for at least two people from April to October!

There is a timer-controlled sprinkler irrigation system to supply the grass with all the water it needs, but the watering schedule is flexible depending on rainfall. In Luther Ely Smith Square (below the Old Courthouse on the map above) the grass and all other plants are irrigated with stormwater that is filtered and stored in a 36,000-gallon water retention basin. Though the grass is reseeded every year – grooves are cut in, then grass seeds are put in the grooves – it doesn’t get stripped and resodded unless something big happens. When one considers the thousands of people who could be walking on the grass on any given day, the resilience and health of our turf grass is remarkable!

The monoculture-lined walking paths (allées) are considered character-defining features of the Gateway Arch’s landscape design. As a contributing feature to a historic landscape listed on the National Register of Historic Places, the allées are protected under National Register Criteria A and C. Learn more about the significance of this historic cultural landscape here and here . The London Plane Trees have been on the Arch grounds since 2016. The previous allée monoculture species, Rosehill Ash, was removed in 2014 in advance of Emerald Ash Borer’s inevitable arrival to St. Louis. London Plane Trees are hybrids of Oriental Plane ( Platanus orientalis ) and American sycamore ( Plantanus occidentalis ). Ours are Bloodgood cultivars, which are known for their tolerance of urban conditions. Because they are non-native, the trees are not part of many food webs, though some bird species have been observed snacking on the seed pods. It will probably take at least 15-20 years for the trees to reach their full height, which could be from 70-100 feet tall. Because the allées are tightly spaced and therefore subjected to shaded and crowded conditions, it is more likely that the London Plane Trees will be on the shorter end of that height estimate. They are unlikely to grow as large as the species could in a more open location. The trees were fertilized and irrigated when they were first planted, but after they reached around three years of age and had developed a robust root system the irrigation was halted. Now, all the irrigation they receive is rainwater and overspray from the irrigation of the turf grass. So far, they appear to be in excellent health.

The Baldcypress (sometimes spelled Bald Cypress) trees on the arch grounds are some of the oldest in the landscape; some of them were planted prior to 1980. Though there are beautiful mature Baldcypress trees in several locations throughout the arch grounds, they are easiest to find in the Baldcypress circles (the red circles to the on the upper left and upper right corners of the map above). Baldcypress is a stellar tree for this area. They have performed very well here, with minimal insect and disease issues. The tree can handle polluted air, flooding, and intense drought. They have even thrived amongst the concrete of Leonor K. Sullivan boulevard. The only Baldcypress on the grounds that has ever needed to be removed was an individual struck by lightning that did not recover from its injury. The trees receive no special treatment, such as irrigation or fertilizer. Because Baldcypress are deciduous trees, they do drop their needles every fall. If you notice the needles turning red or falling off, don’t be alarmed. Visitors are invited to walk inside the Baldcypress circles during their visit. The clearing surrounded by evenly spaced tall trees provides peace and tranquility in a very urban setting.

Our native meadow is almost 3 acres and consists of mostly Big Bluestem and Little Bluestem. The meadow is meant to resemble a native prairie similar to what existed here prior to European settlement. However, here in our very urban built setting, it requires a lot of upkeep to stay healthy. Gardeners must remove unwanted plants regularly. Since so many nearby non-native plant species spread their seeds by wind or birds, new weeds are constantly sprouting up, especially Johnson grass and cattails. Flooding is also a management concern here. When the bottom section of the prairie floods, unwanted seeds are deposited and grass is killed by being submerged in water. The meadow is mowed once in the late spring, around April. It’s mowed at that time so ground-nesting birds can finish fledging their young prior to disturbance. If the meadow were located in a rural setting, burning would be preferred, but due to its proximity to important city infrastructure, mowing is safer and easier while still being highly effective. Below is a list of dominant plants in the meadow: Panicum virgatum (Switchgrass) Schizachyrium Scoparium (Little Bluestem) Andropogon Gerardi (Big Bluestem) Sporobolus Heterolepis (Prairie Drop Seed) Bouteloua Curtipendula (Sideoats Grama) And here are blooming plants commonly found in the meadow:

Until 2015, the north end of the park was dominated by a concrete parking garage. This garage was removed as part of the CityArchRiver renovation project to remove barriers between attractions in the downtown area and to incorporate more green space. Studies had also shown that there was ample parking (more than 2,000 spots!) downtown within a five-minute walk of the Arch. The soil under the garage was heavily compacted, but our talented gardeners were able to bring nature back into the space. The former parking garage is now the Explorer Garden and native meadow, as well as turf grass and pedestrian walkways. The Explorer Garden was planted with the intention of creating space for native pollinators. As such, most plants are native. The goal is to have plants to support insects throughout every season of their life cycle. There should always be something in bloom throughout the entire growing season. The garden is not as highly manicured as other built landscapes on the Arch grounds. For example, dead brush is left standing all winter to provide food and shelter for pollinators instead of being immediately pruned back for aesthetics. Since the Explorer Garden is made of perennials, the boundaries between plantings change year by year as certain species drop their seeds and migrate slightly. As such, it’s impossible to create a map showing precisely where each species is located. However, below is a plant list of species located in the garden.

Many urban-adapted mammals live throughout St. Louis, including at the national park. Animals who do well in urban environments are sometimes referred to as synanthropes, or urban exploiters. Synanthropes are often found at greater densities in cities than in more "natural" locations. If you live in a city or town, chances are good that you've seen pigeons, Canada geese, feral cats, raccoons, white tailed deer, and rats sharing your neighborhood. All of these animals are synanthropes, and all have rising populations. In fact, there are now over 100x more deer in the USA than there were in 1900! Here at the Gateway Arch, squirrels and rabbits are ubiquitous and frequently seen by tourists. However, with luck and patience, several more secretive mammals can also be found here.

Since spring 2019, professional biologists who hold research permits from the National Park Service have been researching wildlife here at the park and at several other locations around St. Louis. For a few weeks four times a year, the biologists set up a motion-activated camera near a scented lure tablet. Later, human volunteers review the pictures and identify the pictured species. Below is their data for our park.