In the Falkirk Council area around 20 per cent of households have still to submit their census return.
The deadline was due to be May 1 but it was announced today by the Scottish government that it would be kept open until May 31.
Around 68,000 households have begun their census returns online but have not yet been completed and a similar number of requested paper forms have yet to be returned.
Every household is legally required to complete their returns and people living in Scotland are reminded that failing to do so could result in prosecution and a fine of up to £1000.
Census letters were sent to 2.7 million homes, representing 5.5 million people.
Two million households have filled in their survey responses, equating to 77.2 per cent, but an estimated 604,000 had still to submit them last week.
Urging people to complete the form, Angus Robertson MSP, Cabinet Secretary for the Constitution, External Affairs and Culture said: “It is vital that we secure as high a response rate as possible so that the census can be effective in delivering its many benefits for future public services. For anyone that hasn’t completed their census, I would urge them to act now.”
He added: “We have now seen well over two million household returns across Scotland and I want to say a huge thank you to those who have done so. However, it's essential we maximise participation and ensure that everyone is heard and their needs captured.
"That is why the census completion site will be left open, support will remain in place and NRS will continue to accept paper returns for this short extension period.
"We know that there are many people who have begun the census online but haven’t completed it, and that thousands of others have requested a paper copy but haven’t yet returned it.”
Help and support to complete the census is available on the website census.gov.scot or via the free helpline 0800 030 8308. Paper forms are still available on request for those who need them.
The 2022 census asks questions on a range of topics, including the types of accommodation people stay in, household relationships, age, sex, health and employment status.