Goofs

When Pardner (Clint Eastwood) and his brother have their accident, they roll down a steep hill. They are at the base of the hill when his brother is buried. For the rest of this movie, the shots showing their claim and camp or cabin site, no hill is seen.

Between the time when Ben firsts sees Elizabeth nursing the baby and when he bids for her his hat gets crumpled various ways back and forth several times.

When Ben Rumson is checking out Pardner and his brother, Pardner wakes up and asks about his brother. As the camera shots change, you can see Pardner with a mostly clean face with an injury above his eye, to a dirt and mud caked face with the injury covered in dirt also, then back to just a clean face with an injury above the eye again.

After Ben Rumson pours drinks at the bar, young Horton Fenty picks up his drink in one hand. But when the shot changes, he's clutching the drink in both hands.

When the group is discussing buying one of the Mormon's wives Tabor who is against the purchase of her for a wife declares that she is a married woman and Holbrook states "No she isn't! We don't recognize plural marriages in California!". But they do later when Mrs. Rumson comes up with the idea to marry pardner too. However, it was earlier stated in the film that Elizabeth is married to Ben Rumson through the governing of mining law, which also covers the point that mining partners get equal share of what is recognized by mining law as their claim. The Rumsons and Pardner use the latter fact as a loophole to justify the plural marriage.

When the town is falling apart in the end, we see the wires used hold up a falling bathtub.

When the town falls apart due to the tunnels collapsing, the smooth sides of the concrete tunnel are visible after the thin layer of mud falls down into them.

When the town is falling apart, you can see the strap holding Horton and the prostitute he's with to the bed as they fall to the ground.

During "The Best Things In Life Are Dirty", Ben Rumson rides up on a cart full of sloppy mud. The three Irishmen, led by Mad Jack, are pulling the cart up on a block and tackle, with a heave-ho motion. The cart should rise a few inches at a time, to synch up with their motions. Instead, while they pull and rest, pull and rest, the cart rises out of the pit at a constant speed.

When the parson arrives in town he is riding up the main street and he stops a moment just before the huge banner that stretches across the street. He hears Atwell ask Mrs. Rumson how her husbands are which shocks him. He calls everyone animals and pagans but then they show him in the next shot as he's starts riding up the street again praying and the banner is now way behind him.

After the discovery of gold and just before we see the sign "No Name City" being painted, there is a panoramic view of the gold discovery. The large (undershot) water wheel serves no purpose at all. Water wheels often were used to power stamp batteries (crushers) but since it is free gold in an alluvial deposit, there is no need for crushing. Also it unlikely that the water wheel was used to pump excavations dry as this would have been impossible given the proximity of the river and the permeability of the alluvials.

Soon after Ben, Pardner, and Mad Jack open their secret "gold mine" underneath No Name City, a young farmer is recruited to help dig. To emphasize the need for secrecy, Mad Jack threatens to shove a stick of dynamite in the farmer's mouth if he blabs. The film is set in 1849 or 1850, before California becomes a state. Dynamite wasn't yet invented (it was patented by Alfred Nobel in 1867).

While working in the "mine", Ben Rumson can clearly be seen wearing a carbide lamp. Carbide lamps were not developed until 1892, but the movie is set in 1849.

When introducing Horton to the cat house, Ben Rumson knocks on the door to the tune of Shave and a Haircut, which wasn't written until at least 1899, and popularized in the 1900s.

At the end of the movie, the tunnel system collapses and the buildings start to topple over. In several shots the cables used to pull over various buildings are clearly apparent, even though it appears that attempts were made to camouflage them with pennants. What gives it away is that the 'pennants' (until the buildings they are attached to topple over) are clearly under far too much strain to be merely hung as decorations.