Tadjinar was a city in the desert several days away from the Lodge and was the home of Lord Amanjira, a wealthy merchant who contracted Ti'ana and her father to scout the desert for valuables. It was the site of Jaarnidu Market, where Anna and her father often obtained supplies; its merchants were not known for their honesty.
Merchants carried wares between Tadjinar and Jemaranir, located to its south.
The events that take place on the surface in The Book of Atrus appear to be set in the Middle East, rather than the American Southwest. Due to this inaccuracy, it is likely that Tadjinar did not actually exist as described in the novel, though it may have been adapted from an actual historical location.