Not all historic districts are created equal. And in Washington, the epicenter of historical monuments, every rock, brick, and building (probably) has a story that someone considers historically significant. There are multiple levels of historical authority: federal level, which is usually administered by the National Park Service (NPS) and listed on the National Register of Historical Places, state level, and the local level. The NPS will break down the historical classification even further depending on what it's designating: object, district, site, building, or structure. In a role reversal, the strictest is usually the local level historical designation since it's the local jurisdiction that yays or nays land use requests.
And where did this all begin? Improbably, the first historical district was set up in Charleston, South Carolina in the early 1930s. The City of Brotherly Love followed suit in the mid 1950s. The idea was that the nabe's vibe was more than the sum of its parts, or in the nomenclature of the time "tout ensemble". So all of the homes, businesses, etc. on a street or on a block contributed to the je ne sais quoi of the area. You know, more than a homogenous suburban feeling. And that vibe needed a special designation in order to be protected.
Within a neighborhood designated as historical, individual buildings can have different statuses: contributing and non-contributing. If it's a contributing property, it's exactly what it sounds like: The building has some feature or features that are deemed important and are of historical significance. And using common sense, a non-contributing property is the opposite of a contributing one. And yes, a contributing property could become non-contributing if its historical character is messed up somehow. Transitioning from non-contributing to contributing designations doesn't happen too often.
Now for homeowners, there is some good news. A nomination on the National Register is just that: a nomination. If your new pad is nominated, you can reject that nomination. And if the nabe is up for nomination, then a majority of the homeowners would have to say nay to ensure the historical designation doesn't happen. There are plenty of motivations for wanting to do this.
But historic designations can go overboard. There are more than 2,300 historic districts in the US. Just as some jurisdictions can under-protect properties and cater to the whims of every developer that comes through town, others can over-protect and cater to every NIMBY-ist and designate structures as historical when in fact, their historical value is suspect. Here is a sampling of DC's list of places designated as historical and cataloged by the city's Historic Preservation Office. Just a heads up: The document is more than 180 pages:
· Bladgen Alley (9th and 10th Streets NW btw M and O)
· Parts of Bolling AFB
· Pretty much any embassy
· SW's Central Heating Plant
· The ever-useful Chesapeake and Ohio Canal
· Downtown (pockets of Penn Ave, F, H, and I Streets NW)
· Dupont Circle
· Logan Circle
· Anything else with "circle" in the name
· Embassy Gulf Service Station (yes, a gas station on P St NW)
· Practically any firehouse
· Sections of 14th and 16th Streets NW
· Lots of post offices
· Many university buildings
· The Greyhound Bus Terminal on NY Ave NW
· Historic Districts In The United States [Wikipedia]
· Contributing Property [Wikipedia]
· District of Columbia 2009 Inventory of Historical Sites [Official Site]
· Historic Districts in Virginia [Wikipedia]
· Historic Districts in Maryland [Wikipedia]