RCMP in Smeaton, Sask., say the fire covering about two square kilometres broke out on Friday afternoon.
Fire departments in Smeaton, Choiceland, Whitefox and Nipawin, along with provincial firefighting crews, are working to contain the blaze.
No injuries or property damage has been reported at this time but Highway 35 north of the town of Love has been closed.
The hot, dry conditions across Saskatchewan means there are to be no open fires in parks and many other areas.
Environment Canada says the weather isn't expected to change in the next four to five days, so the province has issued a ban on Crown-owned land.
That includes most provincial parks — especially in the north where conditions are the most extreme.
Steve Roberts in wildfire management says the conditions are the worst he's seen in years.
"We've had periods of high hazard before, but not continued with a long projection, so we have not called a fire ban of this magnitude in the last five years," he said.
The province says all the fires currently burning were man-made and could have been prevented.
There were almost two dozen fires burning in the province Friday.
(The Canadian Press, CKRM)