The city has lumber and fishing interests (perch, whitefish, sturgeon, pickerel, bass, &c. being caught in Saginaw Bay), large machine shops and foundries (value of products in 1905, $ 1, 743, 1 55, or 31% of the total of the city's factory products), and various manufactures, including ships (wooden and steel), wooden ware, woodpipe, veneer, railroad machinery, cement, alkali and chicory.
In 1905 Portland was the first manufacturing city of the state, with a factory product valued at $9,132,801 (as against $8,527,649 for Lewiston, which outranked Portland in 1900); here are foundries and machine-shops, planing-mills, car and railway repair shops, packing and canning establishments - probably the first Indian corn canned in the United States was canned near Portland in 1840 - potteries, and factories for making boots, shoes, clothing, matches, screens, sleighs, carriages, cosmetics, &c. Shipbuilding and fishing are important industries.
Marshalltown is served by the Chicago & North-Western, the Chicago Great Western, and the Iowa Central railways, the last of which has machine shops here.
At the Charlestown navy-yard (1800) there are docks, manufactories, foundries, machine-shops, ordnance stores, rope-walks, furnaces, castingpits, timber sheds, ordnance-parks, ship-houses, &c. The famous frigate " Independence " was launched here in 1814, the more famous " Constitution " having been launched while the yard was still private in 1797.
Across the river is Rock Falls (pop. in 1900, 2176), practically a suburb of Sterling, with foundries and machine-shops and manufactories of agricultural implements, barbed wire and bolts and rivets.