Free 2-Day Shipping on Orders Over $50* - Limited Time Only

Take 20% off one full-price item

Restrictions Apply >
Use Code: SPRING20


Light and packable for short, summery trips.

There's no need to pack an expedition-style sleeping back for a quick summer overnight or backyard camping trip, so save weight and space by grabbing the Big Agnes Cross Mountain 45-Degree Synthetic Sleeping Bag instead. At under two pounds it won't slow you down or fill up your pack, and it'll be comfortable on mild summer nights, unlike a heavy-duty winter bag that'll just make you sweat. To reduce weight as much as possible, the Cross Mountain forgoes insulation on the bottom of the bag, opting instead for an integrated sleeve that uses a sleeping pad as insulation, letting the bag pack down smaller than it otherwise would while the pad keeps you warmer than traditional insulation, which would only compress under your weight. The mostly-recycled Integrity synthetic insulation stays warm even if it gets damp, and if you've got two Cross Mountain bags with left and right zippers, you can even mate them together to make a double bag and cuddle up with a lucky someone.

  • Integrity synthetic insulation with quilted pattern
  • Water-resistant treatment
  • Full-length integrated sleeping pad sleeve
  • Requires a 20in wide rectangular pad
  • Pillow pocket
  • Left- and right-zipper bags can mate together

Share your thoughts

What do you think of the

Big Agnes Cross Mountain 45-Degree Synthetic Sleeping Bag

? Share a...

Write a review

No file chosen

Rather attach a photo from another website?

Rather attach a photo from your computer?

    Add a:
  • Share a photo
  • Share a video


Only jpg, jpeg, png, gif or bmp files please.

Submit Cancel
Now review from the App. Download

Here's what others have to say...

2 5

Froze my butt off, even in July

  • Familiarity: I've put it through the wringer

I was looking to reduce my pack weight during a 2014 AT thru-hike. I thought I could drop my nearly 3 lb winter weight bag for a summer bag, even just for a few months. At first, I was thrilled with the great packability and light weight of this bag. But, I seriously froze my tush off every night, in 50-70 degrees (early June through late July)! I would wake in the wee hours and wrap whatever I had handy around my body to stay warm, and shiver my way to morning. This thing does NOT rate to 45 degrees. Additionally, I was annoyed to find that the material is so lightweight (um, cheap) that the seams were coming apart after only a month of use, and the velcro on the "pillow" pocket was creating pulls and holes in the bag fabric. BTW, the pillow pocket is useless, because it's so slippery. And on warm nights your face just sticks annoyingly to the fabric. Yuck, all around, a bad buy. I switched back to my winter weight bag in August and for comfort & durability vs weight, I did not regret it.

5 5

Great wamer weather sleeping bag

  • Gender: Male
  • Familiarity: I've put it through the wringer

Check out my video review I posted here to get a better overview of the Cross Mtn. 45. My YT channel also has reviews for other Big Agnes products and other outdoor gear.

Im 6'4". If you over 6ft get the long. Reg is 72*20 Long is 78*20

45 degree temperature rating. It has kept me pretty warm, but I dont think you would want to use it much colder than 45.

Made of 97% sythentic insulation.

Weighs just under 2lbs in the bag that it comes with. I suggest buying a Granite Gear stuff sack for it. Its also so small that it will fit in a stuff sack along with another sleeping bag.

I also have the BA Lost Ranger 15 degree bag and the 2 work awesome together. You put the Lost Ranger inside the Cross Mountain 45 and it brings the temp rating down to 0 degrees. The 2 bags together weigh just over 5lbs. They have the same zipper and can be zipped together. Ive done it. Works great, easy to do.

The great part of the BA sleep system is the pad slides underneath the bag via a slit. This keeps you and your pad connected and you cant slide off you pad at night.

Overall, a great summer bag. Highly recommend it.

Size vs. Nalgene bottle

Size vs. Nalgene bottle

This is without a stuff sack. If you use a stuff sack this bag will compress down to nothing bc its so light.

2 5

Summer only...

  • Familiarity: I've used it once or twice and have initial impressions

Provides little insulation, suitable only for 60+ degree weather. I normally run warm but I had to wear every jacket and layer I had with me to keep warm at 40-45 degrees, sharing a 2-man tent.

Can you unzip the bag to let your feet...

Can you unzip the bag to let your feet out?

What size will it pack down to?

Best Answer Responded on

Hi kst5556641,

It won't unzip all the way at the bottom to let you walk around, if that's what you're talking about. It stuffs down to 7.5in x 15in. Hope this helps!


Responded on

Thanks Casey! That helps!

Do you know if this unzips all the way so that it can also double as a blanket?

Responded on

It unzips far enough that if a couple had two of these bags, or even bags with the same size zipper as this one (i.e. 70" YKK #8 zipper), it would be possible to mate them together. With that possibility in mind, it would stand to reason that you should be able to unzip it far enough to convert into a blanket if you had only one of these instead of two.
Obviously it wouldn't be perfectly symmetrical due to the slightly rounded edges on the bag, but it would be darn close.
Hope this helps.