There are a lot of details you haven't included in your original post Marriage of Margaret Mills, father Charles Mills (coachman) to Robert Stockdale took place in Derry Registry Office-https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1874/11244/8123479.pdf
Occupation given as labourer but only other Charles Mills death in Derry registration district in 1800s- widower and daughter Eliza J, Mills was informant-https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1898/05821/4648157.pdfDerry Journal, 30 Sept.1898: MILLS- September 28, at his residence, Waterside, Londonderry, Charles Mills, aged 73 years. His remains will be removed for interment in ... burying ground this (Friday) morning, at ten o’clock. Friends ...
Off out now so good luck. Lots there to look at.
Samuel Mills, son of Charles Mills (servant) married 1870 Eliza Jane Starret (this may be the 'daughter' Eliza J. Mills that was informant of the Charles Mills who died in 1898).https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1870/11383/8179452.pdfCorrection- informant was 'daughter-in'law'Derry Journal, 25 Mar.1895: Mills—March 23, his father’s residence, Stradreagh, Ernest, the dearly beloved son Samuel and Eliza Mills, aged _ years. His remains will be removed for interment in Glendermott New Burying ground to day (Monday), 25th inst., at ...Samuel Mills also a coachman-https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1900/05761/4627660.pdfhttp://www.census.natithis looks correct. i had found the record for Samuel Mills but i wasn't sure if this was Charles's son. With the 1911 census of Scotland and the 1901 confirming that Eliza' and Samuel's son Robert was a carpenter from Derry, this backs up the Irish 1901 census info as well.
You've started this thread on the Monaghan board but the family were actually found in Derry which means it took more searching to find the correct family.Since we know know that Charles Mills died in 1898 and was a widower you'll need to search for death of wife before 1898. Civil registration of births started in 1864 so if she died before that date there will be no death certificate.William Charles Mills born 1870 Monaghan, parents Charles Mills & Anne Forster-https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1870/03345/2226269.pdfParents married 1852-https://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1852/09426/5414811.pdfDaughter Matilda born 1868-https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1868/03452/2267335.pdfDaughter Emily born 1873 & married 1900-https://civilrecords.irishgenealogy.ie/churchrecords/images/birth_returns/births_1873/03208/2176317.pdfhttps://civilrecords.irishgenealogy.ie/churchrecords/images/marriage_returns/marriages_1900/10347/5766710.pdfWas following the above family in case that Charles was later listed as coachman but nothing. This looks like his death so you can probably forget about them although it does show Mills was a very common surname in Monaghan and there were at least 2 named Charles arounf the same time.https://civilrecords.irishgenealogy.ie/churchrecords/images/deaths_returns/deaths_1896/05882/4668083.pdf
