usually depends on the year. this year has been cold and ice in most places in thick and may last till the end of march. however the ponds around Bozeman on the valley floor may not be safe mid to late march. if staying close to Bozeman is your priority consider hyalite reservoir south of town. it contains cutthroat, brookies, and grayling. most of its shoreline is easily accessible. its ice should hold till the end of march but remember that there is an agreement to close the road to vehicles april first at the mouth of the canyon. so the reservoir cant be reached by walking to it. other waters such as canyon ferry, ruby, and some of the lesser known reservoirs close to bozeman may or may not have ice (or be safe) mid to late march. good luck.
