The Susquehanna estate was an important site in colonial Maryland history. Located on a picturesque bluff near the southern mouth of Maryland’s Patuxent River, it was a convenient place for collection of the king's customs from ships carrying tobacco and other goods. This was “a post which invited many a bitter quarrel.” Susquehanna was the home to three Protestant royal customs collectors who would find themselves murdered during the 17th Century, two by associates of the Catholic governor and proprietor Charles Calvert, 3rd Lord Baltimore. The second and third murders played important roles in the political upheaval that resulted in the overthrow of the Calvert proprietary by the Protestant Associators on 1 August 1689, with the King finally sealing the order to appoint a permanent royal governor and end Lord Baltimore’s governorship on 27 June 1691.

The Rousby era of Susquehanna began when lawyer Christopher Rousby married Elizabeth in about 1669, the widow of the estate’s previous owner, Richard Collett. There were many notable events surrounding the Rousby era of Susquehanna: the murders of three interrelated customs collectors who all resided there; Christopher Rousby’s unrecognized illegitimate son, Charles Boteler; the title challenges from the Rousby family that remained in England following the untimely deaths of the brothers Christopher and his brother John Rousby I; and the enigmatic 1744 will of John Rousby II, wherein Susquehanna was left to his already-married mistress and his two unrecognized illegitimate daughters were named as successors, creating further problems involving the clear title to Susquehanna. Although the Rousby era of the estate could be said to have ended in 1758 with the marriage of the heiress Araminta Thompson (illegitimate daughter of John Rousby II) to Capt. Henry Carroll, the title was not cleared until a 1767 writ of entry sur disseisin in le post was filed with the state of Maryland -- 83 years after the 1684 murder of Christopher Rousby.

The untimely 1684 and 1685/6 deaths of brothers Christopher and John Rousby I left Susquehanna in limbo for almost 50 years and farmed by an absentee landlord. John Rousby II, son of John Rousby I, settled his family on the northern mouth of the Patuxent River at Rousby Hall. Finally, in 1744, after the death of John Rousby II, Susquehanna was left to his already-married mistress Mary (King) Thompson, wife of John Thompson, and their two illegitimate daughters: Araminta and Mary. Mary was deceased without heirs by 1767, which left the estate to Araminta Thompson, who married Capt. Henry Carroll (abt. 1727 - 1767) in about 1758, thus beginning the Carroll era of Susquehanna. Capt. Henry Carroll was a distant cousin to Charles Carroll of Carrollton (1737 – 1832) and Archbishop John Carroll (1735 – 1815). This cadet line of Carrolls includes Maryland Governor Thomas King Carroll (1793 – 1873) and political strategist, author, and fervent Know Nothing activist Anna Ella Carroll (1815 – 1894), both of Somerset County. The descendants that remained in St. Mary's County held Susquehanna until the late 1800s. Descendants of a John Joseph Carroll of Medley Neck (b. abt. 1824 or 1825) remained in St. Mary's long after the Susquehanna Carrolls, until the present day, but there is not any definitive evidence connecting John Joseph Carroll to the Susquehanna Carrolls, though naming patterns of the two families (particularly the names Julia and Henry James) indicate that they are almost certainly related.

A later manor house from the Susquehanna estate, dating from the 1830s, is still standing and is open to visitors, strangely not in Maryland, but in Michigan. After the 13 December 1941 eviction notice was served on all of the residents of Cedar Point in St. Mary’s County, Maryland for the war-time construction of the Patuxent River Naval Air Station, owner Samuel Young offered Susquehanna’s manor house, milk shed, and crypt to his friend Henry Ford for inclusion in the ambitious open-air Greenfield Village museum in Dearborn, Michigan. In Maryland, the original site of Susquehanna is undeveloped and marked with descriptive and attractive signage, but can only be visited by those with access to Patuxent River Naval Air Station. At various times both the Edison Institute of the Ford Museum and the United States Navy have conducted archival and background research concerning Susquehanna, providing evidence to support the Navy’s archaeological digs and the interpretation of Susquehanna at Greenfield Village.