Born in Virginia and a supporter of King George III, Agnew’s interaction with the Black Loyalists occurred early while fighting for Lord Dunmore at the Battle of Great Bridge in 1775. Before the wars end, Agnew would languish in a French prison after being captured. After the British defeat, Agnew crossed the English channel to London to present to the Loyalist Claims Commission, where in 1789, he met Benjamin Marston, former loyalist and disgraced ex-surveyor of Shelburne, Nova Scotia. Marston convinced Agnew to accompany him to New Brunswick to settle.
The Agnews obtained a large land grant and then purchased land straddling the mouth of the Nashwaak River. He named this new estate « Monkton ». Agnew also managed to obtain the rights to operate ferries across both the Nashwaak and Saint John Rivers.
Agnew also had a chaotic political career that saw him pinwheel in his political outlooks. But as a gentleman farmer and ferry operator, he needed a reliable source of labour. This may be the motive behind his strong pro-slavery stance. Agnew, like Caleb Jones (the Nancy Trial), found himself in court acting as proponents of slavery on the basis of property law, considering the enslaved to be similar to livestock and not as people.
This site is rumored to have been the location of the Agnew mansion and slave quarters.