Facts & Figures
The Mackinac Bridge is currently the fourth longest suspension bridge in the world. The bridge opened to traffic on November 1, 1957.
LENGTHS
| Total Length of Bridge (5 Miles) | 26,372 Ft. | 8,038 Meters |
| Total Length of Steel Superstructure | 19,243 Ft. | 5,865 Meters |
| Length of Suspension Bridge (including Anchorages) | 8,614 Ft. | 2,626 Meters |
| Total Length of North Approach | 7,129 Ft. | 2,173 Meters |
| Length of Main Span (between Main Towers) | 3,800 Ft. | 1,158 Meters |
HEIGHTS AND DEPTHS
| Height of Main Towers above Water | 552 Ft | 168.25 Meters |
| Maximum Depth to Rock at Midspan | Unknown | Unknown |
| Maximum Depth of Water at Midspan | 295 Ft. | 90 Meters |
| Maximum Depth of Tower Piers below Water | 210 Ft. | 64 Meters |
| Height of Roadway above Water at Midspan | 199 Ft. | 61 Meters |
| Underclearance at Midspan for Ships | 155 Ft. | 47 Meters |
| Maximum Depth of Water at Piers | 142 Ft. | 43 Meters |
| Maximum Depth of Piers Sunk through Overburden | 105 Ft. | 32 Meters |
CABLES
| Total Length of Wire in Main Cables | 42,000 Miles | 67,592 km |
| Maximum Tension in Each Cable | 16,000 Tons | 14,515,995 kg |
| Number of Wires in Each Cable | 12,580 | |
| Weight of Cables | 11,840 Tons | 10,741,067 kg |
| Diameter of Main Cables | 24 1/2 Inches | 62.23 cm |
| Diameter of Each Wire | 0.196 Inches | .498 cm |
WEIGHTS
| Total Weight of Bridge | 1,024,500 Tons | 929,410,766 kg | |
| Total Weight of Concrete | 931,000 Tons | 844,589 kg | |
| Total Weight of Substructure | 919,100 Tons | 833,793,495 kg | |
| Total Weight of Two Anchorages | 360,380 Tons | 326,931,237 kg | |
| Total Weight of Two Main Piers | 318,000 Tons | 288,484,747 kg | |
| Total Weight of Superstructure | 104,400 Tons | 94,710,087 kg | |
| Total Weight of Structural Steel | 71,300 Tons | 64,682,272 kg | |
| Weight of Steel in Each Main Tower | 6,500 Tons | 5,896,701 kg | |
| Total Weight of Cable Wire | 11,840 Tons | 10,741,067 kg | |
| Total Weight of Concrete Roadway | 6,660 Tons | 6,041,850 kg | |
| Total Weight of Reinforcing Steel | 3,700 Tons | 3,356,584 kg |
RIVETS AND BOLTS
| Total Number of Steel Rivets | 4,851,700 |
| Total Number of Steel Bolts | 1,016,600 |
DESIGN AND DETAIL DRAWINGS
| Total Number of Engineering Drawings | 4,000 |
| Total Number of Blueprints | 85,000 |
MEN EMPLOYED
| Total, at the Bridge Site | 3,500 |
| At Quarries, Shops, Mills, etc. | 7,500 |
| Total Number of Engineers | 350 |
IMPORTANT DATES
| Mackinac Bridge Authority Appointed | June, 1950 |
| Board of Three Engineers Retained | June, 1950 |
| Report of Board of Engineers | January, 1951 |
| Financing and Construction Authorized by Legislature | April 30, 1952 |
| D.B. Steinman Selected as Engineer | January, 1953 |
| Preliminary Plans and Estimates Completed | March, 1953 |
| Construction Contracts Negotiated | March, 1953 |
| Bids Received for Sale of Bonds | December 17, 1953 |
| Began Construction | May 7, 1954 |
| Open to traffic | November 1, 1957 |
| Formal dedication | June 25-28, 1958 |
| 50 millionth crossing | September 25, 1984 |
| 40th Anniversary Celebration | November 1, 1997 |
| 100 millionth crossing | June 25, 1998 |
Events 