Oregon And Washington Are Home To The Two Cleanest Cities In The US, Per A 2025 Study

Have you ever stepped off a plane and noticed how clean the air feels? Or wandered through a new city and realized how little litter there is scattered around? Whether you're sensitive to air pollution, don't want to slip on a banana peel, or simply don't consider Pizza Rat a tourist attraction, your top picks for your next minibreak might just be Portland, Oregon, and Seattle, Washington. The two Pacific Northwest metropolises are the U.S.' cleanest cities, according to a 2025 study by OxiFresh.

The study looked at metrics including air and tap water quality, rodent and cockroach activity, and the presence of litter and visible signs of vandalism. Population density was also taken into account, as more crowded cities tend to face greater challenges when it comes to air quality and waste management. Overall, Portland bagged the No. 1 spot, earning an A+ for cleanliness, with the best air quality of any city in the study — so you really can breathe easy in Portland.

Seattle took second place, securing the Pacific Northwest as one of the cleanest regions in the country. Both are exciting cities to visit, with diverse food scenes, gorgeous waterfront views, and convenient access to the outdoors. It's also easy to do a multi-city break, as Seattle and Portland are two of the stops on Amtrak's incredibly scenic Coast Starlight journey along the West Coast.

Portland has long been a pioneer of clean, green living, and the first thing you're likely to notice (or rather, not notice) is the lack of litter and how few vandalized buildings there are. Start your trip in the walkable downtown, where you can drop in on the Portland Art Museum and take a seat in Pioneer Courthouse Square, aka "Portland's Living Room," and watch the world go by. Then, head to Tom McCall Waterfront Park, one of over 200 parks in the city, to discover 1.5 miles of tranquility.

While in the park, consider hiring a bike and discovering some of the city's 400 miles of cycle paths. The bike-share scheme Biketown has a station in the park, and from there, you can ride a loop over the Steel Bridge and along the Eastbank Esplanade, with 2.6-mile or 10-mile loops available. Either way, you'll get picturesque views of the Willamette River as you enjoy the clean air.

If you're looking to escape Downtown Portland, make your way up to green, serene Tabor Park, where you can see a gorgeous sunset from the peak of the extinct volcano. After that, it's time for dinner and to discover why Portland is the perfect addition to any foodie's bucket list. From food carts serving up almost every cuisine you can imagine to award-winning restaurants, and a smorgasbord of vegetarian and vegan options, you'll be spoiled for choice.

Despite being much more densely populated than Portland, Seattle bagged the No. 2 spot on OxiFresh's list. Just like Portland, Seattle prides itself on its eco-friendly credentials, and similarly, it's a top biking city. The 20-mile Burke-Gilman Trail is the perfect introduction to the city (e-bikes are permitted!). It skirts the shores of Lake Washington, heading through buzzing neighborhoods like the University District before finishing at the scenic Golden Gardens Park on Puget Sound. Just next to the park, you'll find a place to rent kayaks so you can get out on the water and have a chance to spot the whales that live there year-round.

Back in the city, dive into Seattle's thriving arts scene by taking a walk around its clean and colorful streets. Don't miss the lofty and interactive Sonic Bloom sculpture, which sits just below the Space Needle, one of Seattle's most famous attractions; and the beautiful enamel mural in Pike Place Market. Visiting the market is one of the many free things to do in Seattle, so take a wander around the independently owned shops and restaurants, selling locally made crafts and serving fresh eats.

Once night falls in Seattle, it's time to discover Kerry Park, with its spectacular views of the illuminated skyscrapers of the Central City and across Elliott Bay. End your day by heading to one of several of the city's craft breweries, many of which are a short stroll from each other.