The Law Society says that housing advice deserts across the country are "catastrophic", and that the situation risks rendering vulnerable households' legal rights meaningless.
New data from the society shows that households in Doncaster have no state-funded face-to-face advice service for housing issues.
Across England and Wales, 183 of 348 local authorities have no housing advice providers, while a further 78 have just one.
Only 87 have two or more providers. The Law Society warned that the lack of providers in a large area can lead to problems among those on low incomes, who might not be able to afford to travel far to see a solicitor.
Society president Christina Blacklaws said: "More than 21 million people live in a local authority without a single housing legal aid service, leaving pensioners, families with young children and people with disabilities or on low incomes struggling to access the legal advice they are entitled to when they are at their most vulnerable.
"Anyone trying to resolve a serious housing problem is likely to need face-to-face professional advice urgently – if the nearest legal aid solicitor is in the next county they might as well be on Mars.
"The Government must ensure everyone who has a right to state-funded legal advice can actually get it when they so desperately need it. Legal rights are meaningless if people can’t enforce them."
The Law Society also warned that housing legal aid providers cannot represent renters if they are already working for their landlords, which could be a hurdle for some tenants in areas with a lack of housing advisors.
Those living in the South West are hit worst, with 92% of the region living in a local authority with one or no provider.
The East of England, where it was 91%, and the East Midlands, at 79%, were also badly affected. A Ministry of Justice spokesperson said: "It is misleading to compare legal aid services to local authority areas as that is not how provision is set – people can be covered by nearby providers or over the telephone if they are unable to travel.
"There are more offices offering housing advice services now than under the previous contract and we are launching a series of pilots offering support to people with social welfare problems like housing, including expansion of early legal advice."