[27] Due to Chehalis being located near several large rivers and resting in a valley, heavy rains and snowmelt has led the city to experience numerous historic flooding events,[28] often recorded between November and February.

Historical accounts and spiritual lessons passed down in the history of Native American people living in and around the Chehalis River tell of major floods in the basin.

A major flood disaster developed in 1986 after 8 inches (20 cm) of rainfall over several days that led to the submerging of the fairgrounds and a contamination spill at a closed industrial site near Millett Field.

[42] At the beginning of the 1910 Chehalis Gophers baseball season, the club and its ballplayers participated in a minstrel show, receiving positive reviews in a local paper.

During the Great Depression, Chehalis and the surrounding cities and counties saw a rise in the participation of "Silver Shirts", a group that followed similar aspects to the Nazi movement of the era.

[47] A trio of female high school students wrote to the magazine, believing that the feature "did not accurately depict the feelings of local citizens" just the insurance man and his followers, and a follow-up photo article from Life in May showcased the city's actual more varied and "American ideals" atmosphere which tended to more highlight inclusion, tolerance and diversity.

[50][51] Residents in the city in more recent years have protested in favor of the Black Lives Matter movement, holding two demonstrations in 2020 at the Lewis County Courthouse after the murder of George Floyd.

[64] The community grew quickly to include Claquato Church, a cemetery, hotels, and several stores and was, for a time, the largest populated town between the Columbia River and Olympia.

The historic downtown and most of the city's amenities lie on the east side of the freeway, nestled at the base of a small range of forested hills.

[74] Both the Chehalis and Newaukum rivers are prone to flooding during periods of abnormally heavy or persistent rain, and the lowlands from the freeway westward are particularly susceptible to inundation.

[81][82] Mandated by the United States Department of Housing and Urban Development (HUD) since 2003,[83] the annual PTC tracks the number of individuals and families experiencing homelessness on a specified date and is usually held in January.

[91] Food processing, which included canned or frozen items, has been a long-term economic sector of Chehalis, expanding in importance during the 1950s after the construction of U.S. Route 12 and Interstate 5.

The mall was home to national chains and major retailers but in 1999, JC Penney's departed the venue and other businesses followed soon thereafter due in part to the growth of other shopping centers in the local area.

[114] As part of a state-wide GFWC initiative, the St. Helen's Club helped to raise funds to purchase land for the Federation Forest State Park near Enumclaw, Washington during the late 1920s.

[116][117] Mackinaw's, which was located at the Hotel Washington, was subjected to fines, loss of a liquor license, and eventual closure for failing to adhere to Covid-19 protocols for restaurants.

[138] In commemoration of the Kenneth Arnold UFO sighting and the city's connection to the event, the downtown district hosts the "Chehalis Flying Saucer Party" which first began in 2019.

It includes symposiums, a parade, musical performances, and UFO-themed activities in the city, with several exhibits about the sighting displayed at the Lewis County Historical Museum.

The route courses thru the historic downtown district and immediate business core with floats and school marching bands the prime spotlight of the event.

Given the moniker, the Chehalis Historic Preservation Commission, the committee's largest listing was in 2005 with 37 homes recognized; all were located in NRHP districts in the community.

[158] The museum contains a volumetric library of military history, and visitors can participate in direct interactions with visiting United States war veterans as well as browse thru a 9,000 square foot gallery.

[170] Located at the Lewis County Historical Museum is the McKinley Stump, a replica of a 6 foot (1.8 metres) tall remnant of a Douglas fir cut down in 1901 near Pe Ell.

As of 2008, Class 1 wastewater, rather than be fully discharged in the Chehalis River as was common practice before the tree farm was created, is used to hydrate the poplar fields through the use of irrigation pipes.

[94] The Chehalis River and Dillenbaugh Creek watersheds in the city are home to migrating coho salmon and the ecosystems support beaver and deer.

Approximately 10,000 US gallons (38,000 L; 8,300 imp gal) of a mixture of creosote and diesel fuel, as well as cancer-causing chemicals such as dioxin and pentachlorophenol used in the treatment of lumber, spread into the surrounding neighborhoods as well as the Dillenbaugh Creek watershed.

[207][75] The $9.5 million hazardous cleanup was undertaken by the Environmental Protection Agency (EPA) and the area was listed in 1988 as a federal superfund site; [208] the remediation was not completed until 1996.

Chamber of Commerce Way connects to the city shopping center and heads over a 1951 railroad overpass[247] and to the original arterial highway before the interstate was built.

A rail company, the Pacific, Chehalis & Eastern, operated a line to Sea Haven; funded by prominent residents, the venture failed by 1891.

The line transported milk from local dairy farms to condensing plants in the city and provided lumber from surrounding timberlands to sawmills and woodworking producers in Chehalis.

[258] Chehalis received grants of $4.45 million in 2021 to build the first hydrogen fueling station in Washington state; it is to be initially overseen by Twin Transit.

[267][268] The primary source for water is the North Fork of the Newaukum River, which the city is allowed to draw, as of 2023, two-thousand acre feet per year (3.1 million gallons per day).