~ Bridges of Time: Exploring Ontario’s Historic Crossings!” ~

Ontario’s bridges are more than ways from A to B, they’re time capsules. From timber trusses tucked into Mennonite country to stone arches laid by Scottish masons and steelwork that rode the wave of the railway age, these structures chart how the province moved people, goods, and ideas across rivers and ravines. What follows is a tour through that evolution, with snapshots of notable historic bridges you can still visit today.

A quick history of bridge-building in Ontario

In the 1800s, timber was the default. Wood was abundant, cheap, and fast to work with, perfect for early wagon crossings and the first rail approaches. But as heavier loads and longer spans were needed, builders shifted to iron and then steel, especially for railway bridges and long highway spans in the late 19th century. By the early 20th century, reinforced concrete arrived and rapidly took over local road bridges because it was economical, durable, and could be shaped into graceful arches, Ontario became particularly fond of the “rainbow” (bowstring) concrete arch for smaller and medium crossings. Movable steel bridges, lifts, swings, and bascules, also proliferated wherever navigation demanded unobstructed channels, notably on the Welland and Trent–Severn waterways.

A good way to “read” the province’s bridge history is to look at types still standing:

• Covered timber bridges protected their decks from weather and rot; they’re now extremely rare in Ontario.
• Stone arches showcase pre-steel masonry craft, often using local limestone or sandstone.
• Iron and steel trusses (including bowstring/wrought-iron forms) mark the railway and early-highway era.
• Reinforced-concrete arches, especially Ontario’s beloved rainbow/bowstring designs of the 1910s–30s, brought sculptural forms to everyday county roads.
• Movable bridges (swing and vertical lift) keep boats moving without severing road networks.

With that introduction, let’s meet some of the province’s older and most interesting bridges.

Bridge spotlights

West Montrose Covered Bridge (“Kissing Bridge”) — 1881, Woolwich (Grand River)

Ontario’s only remaining historic covered bridge is also one of its most beloved sights. Built in 1880–81 by Mennonite barn builder John Bear, the bridge combines wooden sides and trusswork with later supports; the roof and cladding protect the deck from rain and snow, exactly why covered bridges survived so well before asphalt and weatherproof membranes. Today it remains a cherished heritage icon, undergoing a careful rehabilitation program led by the Region of Waterloo.

Pakenham Five-Span Stone Bridge — 1903, Mississippi Mills (Mississippi River)

Laid by Scottish masons O’Toole & Keating with stone from a local quarry, Pakenham’s bridge is a rarity: five stone arches in sequence, believed to be the only bridge of its exact kind in North America. Its beauty is matched by robust construction; in the 1980s it was strengthened with concealed concrete so it could keep serving modern traffic without losing its historic form.

Blackfriars Street Bridge — 1875 (rehabilitated 2018), London (Thames River)

Among the longest working wrought-iron bowstring through-truss spans on the continent, Blackfriars is both delicate and resilient. Manufactured by the Wrought Iron Bridge Company of Canton, Ohio, and erected by Londoner Isaac Crouse, it represents a narrow slice of bridge history when bowstring iron trusses briefly reigned, before more efficient steel designs took over. A painstaking rehab in 2018 kept it carrying people, bikes, and a single lane of vehicles.

Old Mill Bridge — 1916, Toronto (Humber River)

Look twice: the Old Mill Bridge appears to be stone, but it’s a concrete arch with a stone facing, an early example of engineers using concrete for structure and stone for civic beauty. Designed by Frank Barber, a leading advocate for concrete in Ontario, it replaced a wooden crossing washed out by spring freshets that same year. The coats of arms on the spandrels make it a favorite stop on Humber River walks.

Whirlpool Rapids Bridge — 1897, Niagara Falls (Niagara River)

This double-deck steel arch replaced a famous suspension bridge on nearly the same alignment. Civil engineer Leffert L. Buck built the new arch around and beneath the old structure to keep traffic moving, an impressive logistical feat in the days of rivets and derricks. The upper deck still carries international rail (Amtrak’s Maple Leaf), while the lower deck is restricted to NEXUS autos, the whole span perched dizzyingly above the gorge rapids.

International Railway Bridge — opened 1873 (superstructure renewed 1901), Fort Erie–Buffalo (Niagara River)

A critical cross-border rail link, the International Railway Bridge actually comprises two sections with an island in between, and historically featured swing spans to keep the channel open. While the crossing dates to 1873, the visible superstructure was fully replaced in 1901 atop the original 1873 piers, a reminder that “what you see” and “what is original” are not always the same in bridge conservation.

Little Current Swing Bridge — 1913, Manitoulin Island (North Channel, Lake Huron)

The only road link to Manitoulin for much of the year, this one-lane swing span pivots to let marine traffic pass and then slots back to carry Highway 6. A heritage structure beloved by locals (and photographed by everyone), it began life serving rail and later road; today, studies by Ontario’s Ministry of Transportation envision a sensitive replacement while recognizing the existing bridge’s heritage value.

Parry Sound CPR Trestle — 1907–08, Parry Sound (Seguin River)

The CPR trestle is a signature skyline: ~1,695 ft long and ~105 ft high, a procession of deck trusses and girders lofting trains over town and river. Completed in 1907 with the first scheduled trains crossing in 1908, it still funnels northbound rail traffic, proof of just how robust early 20th-century railway engineering can be.

Welland Canal Bridge 13 (Main Street Bridge) — 1927–30, Welland (Welland Recreational Waterway)

Skewed in plan and dramatic in profile, this vertical-lift span is one of the largest on the Welland Canal and a downtown landmark. Its angled towers reflect the geometry of road and waterway; when raised, the whole 70-metre truss clears the channel for boats. It cost nearly $1 million to build—serious money in 1930.

Caledonia (Argyle Street) Bridge / Grand River Bridge — 1927, Caledonia (Grand River)

Canada’s only nine-span reinforced-concrete “rainbow arch,” this 700-ft landmark was built astonishingly fast in 1927. The rainbow/bowstring form was a Department of Public Highways of Ontario favorite in the interwar years, and Caledonia’s is the magnum opus. Weight restrictions and age have prompted a replacement program, but its heritage status and fame mean the story isn’t over yet.

Types of bridges you’ll encounter (and where to see them)

Covered Bridges

Timber trusses protected by a roof and siding. Ontario has just one historic survivor—the West Montrose “Kissing Bridge”, making it a pilgrimage for covered-bridge fans.

Stone Arches

Self-supporting masonry that works entirely in compression. Pakenham’s five arches are the headliner; the province also has earlier stone spans such as the Lyndhurst Bridge (1857), often cited as Ontario’s oldest surviving stone bridge.

Iron & Steel Trusses

From wrought-iron bowstrings (Blackfriars) to later riveted trusses, these frameworks thrive where long, efficient spans are needed with minimal material. Bowstrings are now rare; that’s why London’s is nationally significant.

Reinforced-Concrete Arches (Rainbow/Bowstring)

A distinctly Ontario flourish of the 1910s–30s: concrete “rainbows” arching above the deck. You can see the pinnacle at Caledonia; countless smaller examples appear on back roads across Wellington, Brant, and beyond, often built to standard provincial patterns.

Movable Bridges

Where navigation is king, engineers make the road move:

• Swing bridges rotate horizontally around a pivot (e.g., Little Current).
• Vertical-lift bridges hoist the deck between towers (e.g., Welland Bridge 13).
  Both forms are part of Ontario’s canal and lakes shipping story.

Railway Trestles and Viaducts

Long sequences of steel trusses and girders (often on concrete piers) carry trains high and level across tough terrain; Parry Sound’s giant CPR trestle is a classic still in daily use.

Why these bridges matter

Historic bridges are working heritage. They knit together the landscapes we love to explore, Niagara’s gorge rim, the picnic rocks at Pakenham, the Humber’s riverine parks, while telling a larger story: how Ontario industrialized, how governments standardized designs for safer roads, how communities fought to save beloved structures, and how engineers accommodate both ships and cars without choosing one over the other. The province even maintains heritage guidance to help municipalities evaluate and conserve culturally significant bridges, a recognition that transportation infrastructure can be as worthy of care as any museum.

They’re also remarkably photogenic. Stand below Blackfriars and trace the wrought-iron ribs; watch the lift towers in Welland glow at night; catch the “rainbow” silhouette in Caledonia; time your visit to Little Current to see the span swing for boats; stroll the wood-scented interior at West Montrose and listen to the Grand River underfoot. These are not just crossings, they’re experiences.

Planning tips for an “old bridges” road trip

• Check current conditions. Rehabilitation work sometimes limits access. (For example, West Montrose is in an ongoing rehab program led by the Region of Waterloo, confirm status before you go.)
• Pair bridges with nearby stops. Pakenham has river-edge picnic spots; Parry Sound’s trestle pairs well with harbour walks; Old Mill Bridge connects to the Humber River Trail.
• Look up and below. Many concrete arches are stone-faced; the structural concrete is visible from the underside, part of their charm.

At a glance: the featured bridges

• West Montrose Covered (“Kissing”) Bridge (1881) — Ontario’s last historic covered bridge; timber truss with protective cladding.
• Pakenham Five-Span Stone Bridge (1903) — Unique five-arch masonry span over the Mississippi River (Ontario).
• Blackfriars Street Bridge (1875; rehab 2018) — Rare wrought-iron bowstring through-truss; still carries traffic, bikes, and pedestrians.
• Old Mill Bridge (1916) — Concrete arch with stone facing on the Humber River.
• Whirlpool Rapids Bridge (1897) — Double-deck steel arch over the Niagara Gorge; rail above, NEXUS autos below.
• International Railway Bridge (1873 foundations; 1901 superstructure) — Two-section cross-border rail link with swing spans in its history.
• Little Current Swing Bridge (1913) — One-lane swing span, heritage structure and seasonal lifeline to Manitoulin.
• Parry Sound CPR Trestle (1907–08) — ~1,695 ft long, ~105 ft high rail viaduct dominating the harbour.
• Welland Canal Bridge 13 / Main Street (1927–30) — Skewed vertical-lift bridge, one of the canal’s largest.
• Caledonia (Argyle Street) Bridge (1927) — Canada’s only nine-span reinforced-concrete rainbow arch.