I too have ancestors who served with the Inverness Militia - Donald McGillivray born 24 July 1772 Bochruben, Dores parish, and his son James McGillivray, b 1797, Kiltearn, Ross-shire, a shoemaker and musician. During the Napoleonic Wars, Scotland raised its first Militia. From 1798-1802 men were drawn from Sutherland, Caithness, Argyll, Dumbarton, Bute and Inverness to serve in Militia and Fencible Regiments.
The Inverness Militia was formed in 1802. Men were drawn from the counties of Inverness, Banff, Elgin and Nairn and were commanded by Sir James Grant of Grant, Bart, Lord Lieutenant of Inverness-shire.
The Inverness Militia was designated to the 10th Militia in March 1804. Donald was a cabinet maker to trade, but served as a Private in the militia from 1808 to 1814.
The regiment served on garrison duty throughout Great Britain during the Napoleonic wars - in 1808, the Inverness Militia was based at Ediburgh, as this is where Donald's son, also named Donald, was born. The militia also served in Portsmouth, as another son, David, was born there. the Inverness Militia returned to Inverness from Portsmouth in 1814, and was then disembodied. Thereafter it was called out periodically for training through 1833. During this period, Donald was a master house carpenter and mist probably was still involved to some degree with the Inverness Militia.
In 1833 the Inverness Militia was redesignated the 76th, Donald's son, James, is listed in the OPRs of his first three children, (Scotland's People) as a corporal and drummer in the Inverness Militia. The Inverness Militia was again embodied at Inverness during the Crimean War.
1855-1881 During the Crimean war the Inverness Militia came under the command of the Master of Lovat and was redesignated the 76th Highland Light Infantry. The uniform was changed to Highland Dress. In 1856, the Militia barracks were built in Telford Street, Inverness, to house the permanent staff and stores. In 1857 Donald's occupation was named as Bugle Master of the Militia on the death record of his son Donald.
From 1858 to 1871 the regiment carried out its annual training period at nearby Fort George and after 1872 in a tented camp at Muir of Ord.
Hope this helps.