Yep, as said, almost certainly a lion, as best anyone call tell without seeing it.
Here's a northern wolf track. Squint and you can see the track better. Canine claws are prominent, and the two front toes tend to be almost even with one another.
Below is a cougar hind foot that shows what sort of track it would make. One leading toe is longer, like the fingers on a human hand will tell you which hand you are looking at on a man. Also, the three lobes at the heel of the track are a give away if the track shows them, compared to a nearly straight across heel of the big canine.
Below is a track of a smallish cougar, and one claw shows slightly in the lead track. When a cougar is walking fast on a steep muddy hillside I have also seen quite prominent claw marks as the cat apparently extended them for traction. But all of those are exceptions and as said, most of the time a mountain lion does not show claws marks in its track.
After all that: Rufous, you have more successful cougar tracking experience than almost anyone on the 'fire! You are remarkably humble in asking!