Mobile
trailers are one of the earliest and still most common forms of factory-built
housing. The
mobile
home has its origin in the camping trailers which were first used during
the 1920s when the automobile became common. Over the years, especially
after World War II, trailers were built as inexpensive housing. 
Besides the lower purchase price of trailers than almost any other type of house, trailer dwellers lowered their housing costs because in some communities, especially in the 1950s-1960s, "moveable" structures were not levied property taxes. In most urban communities, trailers are not allowed, and in rural areas, trailers are often zoned into restricted areas called trailer parks. Trailer parks within current city boundaries, as the trailers shown in these photos, were annexed by the city and are "grandfathered" into zoning ordinances.
The materials and designs of mobile homes reflect many of the variations found in houses, such as Art Deco, Tudor Revival, California Ranch, and Split Level designs.
Trailers represent only one of two attempts
to produce factory-made houses in the U.S. This
photo shows one of four Lustron
houses (made of steel with baked enamel finish inside and out) in Eau
Claire, with the only Lustron garage from 1949. These houses and
trailers have no basements. Despite the claim that Americans are practical
and efficient, the inexpensive and low maintenance trailers and Lustron-type houses have never been
acceptable and therefore rather uncommon.
one 
