Tullamore was designated a 'gateway' town in late 2003 by the Irish Government, making it eligible for increased infrastructural investment. The town was bestowed a bronze medal in the government's National Tidy Towns Competition in 2004 and also played host to the 'World Sheep Dog Trials' in 2005 which attracted international interest in the region. The Tullamore Show is held near the town every year.
The town's most famous export is Tullamore Dew – an Irish whiskey formerly distilled by Tullamore Distillery – that can be traced back to 1829. The distillery shut in the 1950s but its traces are still visible in the town. Tullamore Dew is now produced by William Grant & Sons in Midleton, County Cork, but the owners have invested in a new pot still whiskey and malt whiskey distillery, bringing whiskey production back to the town.
In ancient Gaelic Ireland, Tullamore was located in what was then known as the landfill territory of Firceall ruled by the O'Molloy clan. Firceall was then part of the ancient Kingdom of Meath. Following the plantation of Offaly in the 16th and 17th centuries, Firceall was divided into the baronies of Eglish, Ballyboy & Ballycowen, with Tullamore located in Ballycowen.
Tullamore was part of the first English plantation of Offaly in the 1570s. By the mid-1500s the lands that were originally ruled by the O'Molloy clan were securely "planted" and in the hands of the Moore family. From this point on a dynasty was established which endured into the late nineteenth century, commencing with the grant of the Tullamore area, comprising some 5000 acres, to Sir John Moore in 1622. At that time the Tullamore estate included a ruined castle, ten cottages and two water mills. Sir Robert Forth, who leased the lands from Thomas Moore (son and heir of Sir John), built a mansion house c.1641 in what is now the Charleville demesne. Charles Moore, Lord Tullamore, grandson of Thomas, eventually regained possession of the estate and when he died in 1674 it went via his sister to Charles William Bury. Charles William was later (1806) created the 1st Earl of Charleville in a second creation of the title.
On 10 May 1785, the town was seriously damaged when the crash of a hot air balloon resulted in a fire that burned down as many as 130 homes, giving the town the distinction of being the location of the world's first known aviation disaster. To this day, the town shield depicts a phoenix rising from the ashes. The event is yearly commemorated by the Phoenix festival which celebrates Tullamore's resurrection from the ashes following the accident.
The Grand Canal linked Tullamore to Dublin in 1798. During the Napoleonic Wars, a clash between troops of the King's German Legion and a regiment of British Light Infantry who were both stationed in the town, became known as the Battle of Tullamore. Tullamore became county town of County Offaly in 1835, replacing Daingean.