This is a possibility - may be you will recognize the siblings names? Grandparents from Ireland. Do you know when Martha married and to whom - that might help find better records.
Source: "United States Census, 1900," database with images, FamilySearch (https://familysearch.org/ark:/61903/1:1:M93G-SGZ
: accessed 17 July 2020), Margret E Brown in household of John Brown, Northfield Township Northfield city Ward 3, Rice, Minnesota, United States; citing enumeration district (ED) 158, sheet 11B, family 257, NARA microfilm publication T623 (Washington, D.C.: National Archives and Records Administration, 1972.); FHL microfilm 1,240,788.
United States Census, 1900 Northfield Township Northfield city Ward 3, Rice, Minnesota
: John Brown Head Male 47 Illinois/IRE/CanEng
: Mary Brown Wife Female 47 Illinois?IRE/IRE
: Julia A Brown Dau Female 22 Minnesota
: Catharine E Brown Dau Female 20 Minnesota
: Margret E Brown Dau Female 16 Minnesota
: Alexander Brown Son Male 13 Minnesota
: Francis B Brown Son Male 11 Minnesota