Valtheim Towers are located east of Whiterun. The location consists of two towers connected by a bridge at the top of the first tower leading across the river to the base of the second tower. Seven Bandits and a Bandit Chief can be encountered here.
Two Corundum ore veins along the left of the path outside the second tower
Two clay deposits, one under the bridge on the opposite side of the river, and the second a little upstream on the same side (if The Elder Scrolls V: Hearthfire is installed)
Some of Skyrim's citizens can be overheard talking about the Valtheim Fort; once a mythical defensive structure, and explain that all that remains are the towers.
When passing on the road, a leveled bandit, such as a Bandit Marauder or a Bandit Highwayman, demands the a toll of 200. If the player passes a Speech check, the amount can be brought down to 50. Interestingly, passing through on a Horse allows one to avoid paying the toll altogether, since dialogue cannot be initiated while riding a mount.
A chest is rigged to drop a spiked ball in the first tower. Open it, then jump to the left to avoid being hit, or lockpick the trigger mechanism next to the chest to stop the mace from falling.
Be careful when fighting here if you have a horse (even Shadowmere), as when the bandits attack you, your horse will most likely try to climb the towers and fight the bandits. This may lead to it accidentally falling off and dying.
The treasure chest from Treasure Map II is found near here. (Before you can get the treasure you must have the map). To find the chest, go to the towers and head east by the side of the river. As you near the waterfall, there will be a small cut into the path with the chest inside.
Interestingly when shown as a quest target in the start menu it will be labeled as Valtheim Keep (e.g. retrieve Amren's stolen sword from Valtheim Keep.)
If the Bounty letter has not been acquired from the Proventus Avenicci, the Steward of Whiterun, before retrieving Amren's Sword from the Towers, the Bounty quest-line becomes impossible to complete.
If you choose to intimidate the bandit that approaches you for the toll, the game will remove 200 from your inventory (as if you had chosen to pay the toll), despite the dialog showing that your intimidation attempt was successful. The gold is not added to the Bandit's inventory, so you cannot recover it by killing him/her.
If you have completed the quest for Amren's Sword which was held here at this tower and have then gotten the quest for Trouble in Skyrim for the Companions before the game has had time for the bandits to reset it will glitch and will be unable to complete the quest line for the Companions.