Transylvania and England
Time and place are super important in Dracula. Why? Basically, the world (or at least the continent of Europe) was seen as a newly-shrunken place in ultra-modern 1897... and London was starting to seem more than a little creeptastic.
The first line of the novel is a complaint about late trains, so you know from page one that geography is going to be crucial. The characters move around from city to city and from country to country—even from one end of Europe to the other—with remarkable speed. Stoker makes a point of describing all the state-of-the-art, up-to-date, high-tech transportation.
Mina describes herself as a "train fiend"—she memorizes train schedules just for the heck of it, in case it might be useful in the future to know the exact times you could catch a train from point A to point B. (Um. Mina. Get a new hobby, girl.)
And the up-to-dateness of the technology is likewise important. Stoker wanted to make sure that readers felt like the novel was taking place now... when "now" meant "1897." This is hard for modern readers to remember, since telegrams are now obsolete and trains aren't as commonly used for long-distance transportation. But if Stoker were writing now, he'd have Jonathan Harker tweeting from Castle Dracula and Van Helsing taking a bullet train through the Chunnel under the English Channel.
So moving around is important in Dracula, but where exactly are they? Transylvania, where the novel starts, is in southeastern Europe. It's part of modern-day Romania. Castle Dracula is located on the eastern side of Romania, close to the Black Sea. From there, the action moves to Whitby, which is a real town on the Yorkshire coast of Great Britain (toward the northeastern part of the country, if you're looking at a map). Check out the "Best of the Web" section for more on the town of Whitby. The rest of the action takes place in and around London, the capital of Great Britain.
In 1897, London was the center of the British Empire, which still covered a huge portion of the globe. It was one of the biggest cities in the world. Its crowded, maze-like streets inspired a lot of writers at the time (check out Dr. Jekyll and Mr. Hyde, for example). The city was both an awe-inspiring place (as the capital city of the largest empire of the world) and also a place of potential danger—after all, if the city is so crowded that you don't know your neighbors, who knows who might be living in the tiny apartment upstairs?
It could be a mass murderer, like Jack the Ripper (who terrorized London in late 1888). Who knows who could have purchased the creepy old estate next door? It could be a vampire!