Easily accessible within the Carson-Iceberg Wilderness of Stanislaus National Forest. A great beginner backpacking trip. Campfires are allowed (but check at the ranger station in advance for any fire restrictions). There are granite platforms to jump off into the small but deep lake. 7.5 mile trek.
Getting There
Take 108 to Pinecrest Lake to pick up a free backcountry permit at the Summit Ranger Station. (If you reach Strawberry you've gone too far.) Continue past Beardsley Lake to Clark's Fork Road on the left. Cross two bridges and Forest Route 6N06 will take you to the trailhead (County Line Trail Head) at the end of the road, approximately 30 minutes on a well-maintained dirt road.
The TrailFrom the trailhead, a brief but steep climb will lead you to the sign welcoming you to Carson-Iceberg Wilderness. From here, there's a gradual downhill walk to Sword Lake. You'll hike through a meadow that will be bursting with wildflowers if you're here in July or August.
The hike in should easily take less than 2 hours. Pick a campsite with a pre-existing fire ring and practice leave no trace principles.
Once at the lake, be sure to jump off some of the granite platforms that line the shore. Do depth checks before taking the plunge. Generally, if you can submerge yourself completely with your hands above your head you should be able to jump safely.