If it looks like Lady and the Tramp, it's Second Empire.
That's the Fickie Mansion in Davenport, Iowa. It's magnificent, ain't it? I can't find out if it's still there. There's an ominous looking strip mall behind it with a muffler place in the background. It was the fate of many such places to be too central to a well established business district for their own good. Well-to-do people used to live where they worked. Now they'd live out in the landscape and drive in every day. Iowans, let's hear it. Is it still there? Man, it's got everything a Second Empire house would have.
Mansard roof, "cresting" along the rooflines, towers, a cupola, ganged windows, window bays, bracketed windows...bracketed everything, really; patterned multicolored roof, porches.
It was essentially an urban style, but "urban" would look a lot like a village to the modern eye in many cases. From the end of the Civil War until the end of the 1880s, this was the predominant style of the Northeast and the Midwest.
It lent itself to straight-up commercial buildings, too. Here's a Second Empire building in Portland, Maine I've walked by a hundred times:
It was a dry goods store then. More or less, it still is. Retail and offices, anyway. If you went up to the third floor toilet, there were cartoons of U.S.Grant and Buffalo Bill drawn on the wall. That's double funny, as Second Empire was referred to as "General Grant Style" by a lot of people then.
They were hard to keep up. I'd work on them here and there twenty-five years ago, and all the slate roofs were gone, some replaced with painted wood sidewall shingles, or worse- asphalt tab shingles. I've even seen them vinyl and aluminum sided. Jesus wept.
It wasn't a west coast thing, much. Most of the post-bellum houses out there are Stick Style, or Italianate. They're similar in many ways. A lot of millwork--doors, windows, interior trim, brackets and so forth-- was more or less interchangeable in those styles.
The style wasn't big down south. It did make it down to Charleston, South Carolina, though; here's the Ingrahm House for one:
"Second Empire" refers to the reign of France's Napoleon III. It wasn't a revival, like Greek or Italianate or Gothic. It was considered quite modern at the time.
And here's how what was once the predominant style in a great swath of the United States for thirty years can become fairly rare in short order:
The nature of the urban landscape changed. Big old houses became apartment buildings and were cut up and run down, or the land beneath them became so valuable they were demolished to make way for much larger structures.
I bet that last place burned ten times before they gave up and built something else.