Lincolnshire Fire and Rescue Service has the slowest response times in England, according to figures released in Parliament.
Statistics revealed in answer to a question from the Shadow Home Secretary Patrick Mercer show that it takes crews an average of 10 minutes to respond.
Mike Thomas, the county's chief fire officer, said times were increased due to the rural nature of the area.
The fastest service was Tyne and Wear with an average of five minutes.
Mr Thomas said his crews work hard to educate the public on how to prevent fires.
"We don't just respond to emergencies, we actually try and prevent fires and protect the community. Saving life and preventing injuries are the areas we concentrate most on.
"We do want to respond to incidents as and when they happen and we're a very large geographical county... Of course that does pose some problems and that's reflected in the figures.
"In comparison to other rural counties like North Yorkshire, Devon and Cumbria, they have the advantage of having a large national park, so the population is concentrated into smaller areas... In Lincolnshire you drive down the road and every couple of miles, you've got another community," he said.
"The reality is that this is an average time and not a reflection of the pure times. In many parts of the county, particularly in the towns, our performance is much, much better than that," he added.