He was declared a rebel and given a life sentence in a trial after the Rebellion of 1798[3] and was one of a number of political prisoners who arrived in Australia on the Friendship in February 1800.
[4] Two months later he became an assistant to Charles Grimes, the surveyor-general, and went with him to explore the Hunter River in 1801.
[7] He accompanied Hamilton Hume in some explorations in southern New South Wales in 1816, when Lake George was discovered, and in 1818 Meehan was appointed deputy surveyor-general.
He endeavoured in this year without success to find a practicable road over the Shoalhaven River so that communication might be opened up with Jervis Bay, but continuing his efforts early in 1820 he went through some very difficult country after crossing the river from the east, and then connecting with his 1818 track.
He was a most capable and industrious official, and though he does not rank among the leading explorers, he did some very valuable work while carrying out his duties during the first 20 years of the nineteenth century.