[Texas Fossil]

There are no backpack nukes.

The smallest are past human conveyance.

[Travis McGee]

Maybe not now, but there were.

[Timber Rattler]

When hauling the weapons on foot, things were even more difficult. Dan Dawson, an ADM engineer, remembers how difficult it was to run with a backpack nuke. During a training exercise, his unit simulated a mission to blow up a railroad tunnel but found it difficult to move a SADM across a patch of open ground.

"To get [the SADM backpacker] across this open area in a hurry, two of us, one on each side, had to support him under his arms and trot with him across this open area. You could carry it, but you couldn't run with it."

[PapaBear3625]

The W54 device was "10.75 inches diameter (270 mm), about 15.7 inches long (400 mm), and weighs around or slightly over 50 pounds (23 kg)".

A fit man can carry a 50 pound backpack a long distance.

[Renegade]

If there were,where are they now?

[thackney]

The Davy Crockett
http://www.brookings.edu/about/projects/archive/nucweapons/davyc

The W54 warhead used on the Davy Crockett weighed just 51 pounds and was the smallest and lightest fission bomb (implosion type) ever deployed by the United States, with a variable explosive yield of 0.01 kilotons (equivalent to 10 tons of TNT...

[sgtyork]

We war-gamed using them in Command Post Exercises in the 80s.

[kennyboy509]

I have one in my garage.

I bought it at a yard sale.