When the wind blows from the north a pall hangs over not only Decatur, but the entire southern area of Macon County in Central Illinois. This being the byproduct of what is called the savior of humanity, converting soy beans and corn into a myriad of other products. Some say the smell is similar to McDonald's fries, but I have to opt for something akin to rotten eggs and vinegar.
Decatur was named for Commodore Stephen Decatur, a military hero of the early 1890's, who was fortunate not to have any real connection with the city. In fact, history tells us that he may never had set foot in the town that bears his name. In this fact he is one of the fortunate ones. As one passes through Decatur they are struck by the vast number of churches in town, only to be equally impressed by the number of drinking establishments. It's as if the Good Lord, whatever denomination he or she might be, is constantly trying to establish some type of temperance, but failing.
There is the popular Lake Decatur, actually a bulge in what exits its southern boundary as the Sangamon River, where many resident enjoy aquatic recreation. From its banks, Lake Decatur appears dirty, but as many mid-west bodies of water, its only muddy. It's too thick to drink and too thin to plow and not at all appealing for swimming, as one has to dodge the many snakes and other water animals who call it home.
There are a few nice placed to eat in Decatur, namely, Porter's on Merchant, The Lincoln Lounge, Coney McKane's, The Beach House (just don't look at the lake), Tuscany's Steak and Pasta House. and some chain restaurants at the Hickory Point Mall, but check the wind direction lest a whiff of the soy bean / corn manufacture ruins what may have been a great dining experience.
The only lodging establishment worth considering in town is the Decatur Conference Center and Hotel. Once there one really doesn't have need to leave. The rooms are, while not extravagant, are clean and well lighted. There is a choice of three restaurants, one being a sports bar. The food in all three is delightful. There are a wide choice of meeting rooms of all sizes, a heated indoor pool, whirlpool and sauna, and suites with large jacuzzi tubs.
All in all, stay on I-72 if you have a choice. You'll find Springfield or Champaign more conducive to a stay.