Commercial Union Assurance Building

{{Use American English|date=February 2025}}

{{Infobox building

| building_name = Commercial Union Assurance Building

| image = Commercial Union Assurance Building.jpg

| caption = The Commercial Union Assurance Building in July 2015.

| former_name =

| location = 315 Montgomery Street
San Francisco, California

| coordinates = {{coord|37.792111|-122.403|region:US-CA_type:landmark|display=it}}

| pushpin_map = United States San Francisco Central#California#USA

| start_date =

| completion_date = 1921

| status = Complete

| building_type = Commercial offices

| architectural_style = Renaissance Revival

| roof = {{convert|94|m|abbr=on}}

| top_floor =

| floor_count = 16

| elevator_count =

| cost =

| floor_area =

| architect = George W. Kelham

| engineer =

| main_contractor =

| developer =

| owner =

| management =

| references = {{Cite web |url=https://www.emporis.com/buildings/184030 |archive-url=https://web.archive.org/web/20210126162416/https://www.emporis.com/buildings/184030 |url-status=usurped |archive-date=January 26, 2021 |title=Emporis building ID 184030 |work=Emporis}}{{skyscraperpage|10631}}

}}

The Commercial Union Assurance Building is a {{convert|94|m|abbr=on}}, 16-story office building located in the Financial District of San Francisco, California. The building was completed in 1921 and is the same height of the San Francisco City Hall.{{cite web |url=http://skyscraperpage.com/cities/?buildingID=10624|title=San Francisco City Hall| work=SkyscraperPage | accessdate=5 April 2012}} The much taller 555 California Street is to the west of this Renaissance Revival styled building. Floors 9 and 10 are now flexible coworking spaces{{Cite web |title=315 Montgomery Street, San Francisco |url=https://officesearch.com/office/315-montgomery-street-san-francisco/ |access-date=2024-12-13 |website=OfficeSearch |language=en-US}}