Best Tent Camping near Mercer Island, WA

The Red Bridge campground is on the very scenic Mountain loop Rd in the Mount Baker-Snoqualmie National Forest. It's a very beautiful drive. Nestled in some great trees, there are 13 sites with shade, right along the river. The camp host was very nice and sold firewood on site. There are no hook ups, and no water spigots so be sure to plan accordingly. There are bear proof trash cans and vault toilets available. Each site has a tent pad, picnic table and fire ring. This campground provides ample hiking, fishing and I saw people kayaking plus its not far to a hike to some glacier caves! Also check out the old red trestle bridge just outside of the campground. At $15 a night you have to see this place. 
I highly recommend Red Bridge campground.

arrived at the farm and were greeted by the owners. they got on their quads and led us down a private road through a super nice cedar gated entry and showed us our spot. they gave us a quick run down of the place and let us be. our spot was the Trillium site which has a few hundred foot hike from where you park your car and the portable toilet. the site was pretty cool and very secluded. it had a fire ring with some sawn cedar benches, a pile of firewood and a giant old spool for a table. we threw our marmot up and took a closer look. there is a camp box with info, instant coffee, guides to area sight seeing and food along with a log book to write about your stay. there were also some cool led lighting which was great at night. fire ban was on but they put a big candle on the grate of the fire pit so we had something. we kicked around on the trails which look like they are used by horses and motorcycles but not heavily. some interesting plants in the area. they were working on a new trail that is supposed to eventually lead out to the lake but it wasnt complete yet. however it was covered with wood chips and had a hand cut cedar bridge built on it. you gotta see it. sounds like they are constantly evolving the farm looked like a lot of things in the works. definitely will come back for more time here. night time got spooky with coyotes howling in the distance but the morning there were so many birds chirping and singing you couldnt hear yourself think! oh we found a corn hole game in an open area that they have several picnic tables staged at.

This campground is right next to a state park. It’s also very close to a river and lots of woods. We stayed here to see Olympic national park, (I wouldn’t recommend this location to travel to Olympic every day, it was very far.)

The amenities were nice, bathrooms with warm water (one shower per bathroom.)

No laundry, no Wi-Fi and both Verizon and AT&T worked with about one bar.

The sites were level spacious and had a fire ring and picnic table at each. We chose the full hookup option. Firewood could be purchased through the camp host.

The best part about this day was the surrounding area. Every night, my husband and I would walk to the wildlife viewing platform to see lots of birds, or walk down by the river and see lots of elk and bald eagles.

Every dispersed campground we checked along this road (maybe five or so) was littered with human feces and toilet paper everywhere. We found a literal bucket of human waste beside the river with a soiled pool noodle nearby I can only assume was being used as a toilet seat. Please, if you care about keeping nature wild, carry out your toilet paper and dig a cathole or use the outhouse in the campground. If you don’t know what a cathole is, you should probably should not being using dispersed camping and try the campground down the road. We ended up staying at the campground because we couldn’t find dispersed camping where there wasn’t poop and had a positive experience there. Leave no trace!! 

https://www.nps.gov/articles/leave-no-trace-seven-principles.htm

Nothing special about it. It was SUPER clean! The camp was fully booked but the bathrooms and dumpsters didn't smell and were always clean and stocked! No showers, nonflushing toilets and no sinks. Did have water faucets for getting water for washing dishes. Nice big spots, saw several RVs of all classes, couple Eurovans and our Westfalia fit wonderfully! Lots of tent campers too! Had designated flat spots for your tent too. Located right on the Mountain Loop Highway which makes for an easy drive up to see some good scenery but can also be loud with a lot of cars.

I'd choose Verlot Campground next time because it is only a 1/4 mile or so up the road but it has a beach access point.