Joliet is a moderately safe city in the United States. Like any urban area, it has some neighborhoods that are safer than others. As a solo female traveler, you will find most locals to be friendly and willing to help. However, it's always important to stay vigilant, especially during night hours or when visiting isolated areas. Usual measures like staying in well-lit populated areas, having local emergency numbers at hand, and keeping your valuables hidden and secure, will highly contribute to your personal safety.