Editing Lake Superior (section)

===Shipping===
[[File:Ice blockade in Marquette Harbor, June 1873, by Childs, B. F. 2.jpg|thumb|"Ice blockade in Marquette Harbor, June 1873", stereoscopic photo]]

Lake Superior has been an important link in the [[Great Lakes Waterway]], providing a route for the transportation of iron ore as well as grain and other mined and manufactured materials. Large cargo vessels called lake freighters, as well as smaller ocean-going [[seawaymax|freighters]], transport these commodities across Lake Superior. Shipping was slow to arrive at Lake Superior in the 19th century. The first steamboat to run on the lake was the [[Independence (steamboat)|''Independence'']] in 1847, whereas the first steamers on the other Great Lakes began sailing in 1816.<ref>*{{cite book |last = Palmer |first = Richard F. |title = First Steamboat on the Great Lakes |year = 1988 |url = http://navalmarinearchive.com/research/pdf/in_seas_xl_1-7_sm.pdf |pages = 7–8 }}</ref><ref>*{{cite book |title = Great Lakes Ships and Shipping |first = Dana Thomas |last = Bowen |publisher = Minnesota Historical Society |year = 1953 |url = http://collections.mnhs.org/MNHistoryMagazine/articles/34/v34i01p009-016.pdf |page = 9 |access-date = October 28, 2019 |archive-date = July 14, 2020 |archive-url = https://web.archive.org/web/20200714210700/http://collections.mnhs.org/MNHistoryMagazine/articles/34/v34i01p009-016.pdf |url-status = dead }}</ref> Ice closes the lake shipping from mid-January to late March. Exact dates for the shipping season vary each year,<ref>{{cite web |url = http://duluthshippingnews.com/tag/paul-r-tregurtha/ |title = Paul R. Treggurtha: Last Trip for the ''Tregurtha'' This Year |date = January 12, 2015 |access-date = January 21, 2015 |work = Duluth Shipping News |quote = Another trip here was planned but has apparently been canceled, making this her last and 41st visit this season. Last year, without a late start due to ice, the Tregurtha was here 49 times. |archive-date = May 20, 2020 |archive-url = https://web.archive.org/web/20200520193113/http://duluthshippingnews.com/tag/paul-r-tregurtha/ |url-status = dead }}</ref> depending on weather conditions that form and break the ice.