In 1840, the steam-powered Annapolis and Elk Ridge Railroad (A&ER) was built across a sparsely settled farming community that would later become Odenton. At the beginning of the American Civil War, Union soldiers guarded this railroad line because it was the only link between the North and the nation's capital. Rail traffic through Baltimore had been disrupted by southern sympathizers, so supplies, mail and soldiers flowed through Annapolis and West Anne Arundel County to Washington, DC. The town of Odenton, nicknamed "The Town A Railroad Built" by Catherine L. O'Malley, was formed in 1868 with the construction of the Baltimore Potomac (B&P) Railroad connecting Baltimore and Washington, D. C.. Where the B&P crossed the A&ER, a train station and telegraph office were constructed and named for Oden Bowie, President of the B&P and former governor of Maryland. Train service to the station began on July 2, 1872. The rail junction (today's MARC station) at Odenton Road, already a busy thoroughfare from Annapolis to Frederick, became the site of Odenton's first commercial center. The Watts and Murray general stores served railroad workers and farmers and in 1871, a post office was established. A town grew near the junction, houses were built for railroad workers, a Methodist church was dedicated in 1891 and a grade school opened in 1892.
Small villages developed around these various railroad lines, but none amounted to more than a cluster of shops and homes around a train station and post office. The 1878 Maryland Directory listed the following towns: Conaway, Odenton, Patuxent, Sappington, and Woodwardville. Odenton was the largest with a population of 100 with a church and school, and two stores. In nearby Woodwardville, where the B&P crossed the Little Patuxent River, A. G. Woodward was the postmaster and operated a general merchandise store in a village of 50 people. Two churches and a school served that community. Land was worth from $5 and $30 per acre, producing wheat, corn and tobacco.
Canneries, primarily for tomatoes, were built in many locations in Anne Arundel County, including Odenton and Woodwardville. The George M. Murray Canning House, built in the late 19th century on Odenton Road (behind present day 1380 and 1382 Odenton Road) was a successful operation into the early 1900s.
Shortly after 1900, another company built an electric interurban railroad parallel to the B&P and also electrified the former A&ER. Train service on these lines began in 1908. The Washington, Baltimore and Annapolis Electric Railroad provided public transportation to central Maryland.
In 1914, the United States Naval Academy purchased the 800 acre (3.2 km²) Hammond Manor Farm for the construction of a dairy following the 1910 typhoid fever outbreak at the Academy. The Academy operated the dairy until 1998. Until 2005 it was the home of Dean Foods' Horizon Organic dairy. The farm is currently the home of Maryland Sunrise Farm.
In 1917, at the advent of World War I, Odenton’s growth was spurred by the establishment of Fort Meade. The United States Department of War acquired 19,000 acres (77 km²) of land west of Odenton to develop a training camp, displacing numerous farmers, merchants and public and private enterprises; many of whom moved east to nearby Odenton. This growth accelerated in the 1950s with the establishment of the National Security Agency on the fort and Friendship International Airport (now the Baltimore-Washington International Thurgood Marshall Airport) a few miles to the north. Odenton still maintains its railroad history through the Dennis F. Sullivan Maintenance Facility, operated by Amtrak, which maintains track, bridges and other structures on the Amtrak/MARC line between Baltimore and Washington. All of this, as well as the suburban expansion of Baltimore and Washington, D.C., have transformed Odenton from a farmland region to a business, residential and industrial center in Anne Arundel County.
Odenton is located at (39.071276, -76.699756).
There were 7,594 households out of which 37.7% had children under the age of 18 living with them, 58.8% were married couples living together, 10.5% had a female householder with no husband present, and 26.9% were non-families. 19.7% of all households were made up of individuals and 4.2% had someone living alone who was 65 years of age or older. The average household size was 2.70 and the average family size was 3.13.
In the CDP the population was spread out with 26.9% under the age of 18, 7.0% from 18 to 24, 38.7% from 25 to 44, 20.5% from 45 to 64, and 6.8% who were 65 years of age or older. The median age was 33 years. For every 100 females there were 94.9 males. For every 100 females age 18 and over, there were 91.7 males.
The median income for a household in the CDP was $65,563, and the median income for a family was $69,098. Males had a median income of $45,965 versus $32,659 for females. The per capita income for the CDP was $26,124. About 1.6% of families and 2.5% of the population were below the poverty line, including 1.8% of those under age 18 and 5.2% of those age 65 or over.
In recent years the Odenton area has become the fastest growing area in the county. This is because of its location near Fort George G. Meade, NSA Headquarters, and its proximity to Baltimore, Washington, D.C., and Annapolis. The development has been fueled by the construction of the massive Piney Orchard development as well as the soon to be under-construction Odenton Town Center.