Where can I find vampires in Skyrim?

I want to become a vampire so I can suck people's blood. What locations have vampires?

Solution 1:

Vampire locations:
Broken Fang Cave, Bloodlet Throne, Cronvangr Cave, Fellglow Keep, Half-Moon Mill, Haemar's Shame, Mara's Eye Pond, Movarth's Lair, Pinemoon Cave, Shriekwind Bastion, Potema's Catacombs.

^{Source: UESP wiki, "Skyrim: Vampire" article}
For PC users, the mod, DFB - Random Encounters can add various random encounters to the game, including Vampire encounters. You can configure the chance of encountering, difficulty and quantity of the Vampires that you can encounter with the mod.

Also, see this Gaming SE question and its answer(s): Is there any way to ensure you become a Vampire?

If you have the Dawnguard DLC installed, it will add random encounters to the game involving vampires, allowing you more chances to contract Sanguinare Vampiris.

When you play through the main Dawnguard DLC questline, you can also allow Lord Harkon or Serana to turn you into a Vampire Lord.

Solution 2:

Easiest way to become a bloodsucker would be to join the Dark brotherhood. There is a target that is a vampire and your "brothers" will warn you that he is one before you go to kill him. Important is that you strip your char (take of your armor at least) and let him hit you while you are naked. You'll catch the "disease" easier that way. The Npc is called Hern.

I know of a few random places where vampires can be found as well: Pinemoon Cave, Morvath's Lair , Bloodlet Throne and Shriekwind Bastion

Solution 3:

The just-released DLC, Dawnguard, is centered around vampires, and the locations associated with it have tons of them.