The Mercaderes stretch of the encierro route in Pamplona is a brief, narrowing corridor that funnels runners and bulls from the open Plaza del Ayuntamiento into the sharp right turn at La Curva de Estafeta. Calle Mercaderes (pronounced mer-cah-DEH-res), meaning “Merchants’ Street,” runs slightly downhill for approximately 50 meters, narrowing from 8.7 meters to as little as 6.6 meters before diagonal barreras (wooden barriers) widen the chute again near the curve. This section demands spatial awareness, timing, and an understanding of how the herd moves through a compressed space. It is one of the shortest sections of the full 875-meter encierro route, but its combination of narrowing walls, downhill momentum, and proximity to La Curva makes every meter count.
Why Mercaderes Matters in the Encierro
Most coverage of the encierro focuses on La Curva de Estafeta itself, the dramatic right turn where bulls collide with barreras and runners scatter. But what happens on Mercaderes in the seconds before that turn determines how the rest of the encierro unfolds. The herd enters Mercaderes carrying momentum gained from the diagonal crossing of the Plaza del Ayuntamiento, a large open square where the course runs slightly downhill. By the time the bulls reach Mercaderes, they are accelerating.
As Mat Dowsett describes in “Encierro!” (2003), the buildings on Mercaderes force the street to narrow from 8.7 meters at its entrance down to 7.2 meters, and then to just 6.6 meters where the buildings end. The diagonal barreras then open the chute back up to 8.7 meters before the curve begins. This narrowing and widening creates a compression effect. Runners who do not account for it find themselves squeezed into tighter space precisely as the bulls gain speed.
“A bull has confidence when it’s running uphill because it can run at its full strength, but as soon as it’s now on a downhill, has to be somewhat more cautious with its legs.”
Dennis Clancey, Founder of Encierro and member of La Única Peña
This slight downhill gradient is one of the defining features of Mercaderes. The bulls adjust their stride as they descend, becoming more cautious with their footing. But “cautious” does not mean “slow.” The momentum from the plaza carries them forward, and the narrowing street compresses the herd’s lateral movement into a predictable pattern.
The S-Shape: How Bulls Navigate Mercaderes
The herd does not run straight through Mercaderes. According to Mat Dowsett in “Encierro!” (2003), the slight camber of the street, combined with the momentum from the plaza’s diagonal crossing, causes the bulls to traverse Mercaderes in an S-shape. They first hug the right side of the street, then drift back toward the left before the hard right turn into Calle Estafeta.
This pattern is reasonably predictable under dry conditions. On wet mornings, the effect amplifies. Rain on the cobblestones (adoquines) exaggerates the drift caused by inertia, pushing the bulls further right in the plaza and therefore further right entering Mercaderes. As Dowsett notes in “Encierro!,” this creates a cascading effect: what begins as a slight positional shift at the top of Santo Domingo can escalate dramatically by the time the herd reaches Mercaderes.
For runners, this means that the left side of Mercaderes is generally less exposed than the right. The bulls’ natural drift toward the right on entry means runners on that side are more likely to find themselves in the direct path of the herd. Those on the right do have the advantage of a long section of barreras to escape through, but the margin for decision is measured in fractions of a second.
The Sun Glare: A Hazard Most Runners Never Consider
There is an environmental factor on Mercaderes that virtually no written guide mentions, because you would only know about it from being on the street at 8:00 in the morning.
“The sun is sitting just above the facades at the end of Mercaderes at the curve. And so it can be a bright light and can kind of be temporarily disorienting.”
Dennis Clancey, Founder of Encierro and member of La Única Peña
On clear mornings, the rising sun sits directly above the building facades at the far end of Mercaderes, right where the street opens into La Curva de Estafeta. Runners heading through Mercaderes are running directly toward this light. The effect is a momentary flash of brightness that can limit the ability to distinguish what is happening ahead. This is exactly the kind of street-level detail that separates instruction from observation. From a balcony, the sun is not a factor. From the cobblestones, it can be disorienting at the worst possible moment.
This glare is obviously weather-dependent. Overcast mornings eliminate it entirely. But on the clear, warm days that are common during the first week of San Fermin, it is a real consideration for anyone preparing to run the encierro.
Tactical Positioning: Never Stand Still on Mercaderes
The most common tactical error on Mercaderes is also the most fundamental: standing still and waiting for the bulls to arrive.
“You wanna be up to speed by the time the bulls get to your position because, otherwise, you’re kind of a waiting target. It’s impossible to get up speed instantaneously.”
Dennis Clancey, Founder of Encierro and member of La Única Peña
Runners who intend to run through Mercaderes typically start in the Plaza del Ayuntamiento (Town Hall Square). The key is to begin moving before the herd reaches your position. A mozo (runner) who is already at pace when the bulls arrive can make spatial decisions: move left, move right, angle toward the barreras. A mozo who is standing still has none of those options. The physics are simple. A human being cannot accelerate from zero to running speed in the time it takes a bull to close a gap of a few meters.
One tool that helps with timing is the cable camera that now runs over the route in the Town Hall Square area. This overhead camera tracks the lead animal, and runners who are aware of it can use its position to gauge how close the herd is. It provides a visual reference point that was not available to previous generations of runners.
“There is a cable camera over the run route. That cable camera will track over the lead animal and gives you a good indication of how close the herd is. So that you can make sure you’re up to speed.”
Dennis Clancey, Founder of Encierro and member of La Única Peña
The Experienced Runners at the Bottom of Mercaderes
Many of Pamplona’s most experienced mozos choose to start their run at the bottom left side of Mercaderes. As Mat Dowsett observes in “Encierro!” (2003), these runners position themselves here specifically to run up into Calle Estafeta, taking the curve with the herd. This is a deliberate, practiced choice. Running around La Curva de Estafeta carries its own set of challenges, and the runners who start at the base of Mercaderes are typically veterans who understand the forces at play.
For those who choose to position along the right side of Mercaderes instead, the long section of barreras provides a viable escape route and also a prime spectating position. From behind these barriers, you get one of the closest views of the bulls entering La Curva de Estafeta. But the barriers also attract crowds, and during San Fermin, the density of people pressed against them can make a quick exit more difficult than it appears.
A Brief History of Mercaderes on the Route
Mercaderes, previously known as Calle Doña Blanca de Navarra, has been part of the encierro route for centuries. According to Mat Dowsett in “Encierro!” (2003), the street was widened in 1914 by demolishing buildings along its path. Before that widening, the street was considerably narrower and more enclosed, with a structural block that almost separated Mercaderes from Estafeta entirely.
The curve connecting Mercaderes to Estafeta was also reshaped over time. Dowsett notes in “Encierro!” that the curve was originally much more square and did not naturally draw the bulls around the corner. The current shape, a more gradual arc aided by barrier placement, was developed through decades of experience. Even the removal of raised pavements on both Estafeta and Mercaderes in 1998 was part of ongoing improvements to make the route’s surface more uniform for both bulls and runners.
Medical and Safety Infrastructure
Mercaderes has its own dedicated medical team, one of six positioned along the full encierro route. As Dowsett documents in “Encierro!” (2003), the medical stations are positioned at: the bottom of Santo Domingo, halfway up Santo Domingo, the Ayuntamiento, Mercaderes, halfway up Estafeta, and the Telefonica section. These teams respond to incidents within seconds.
The police presence on Mercaderes is also significant. Before the run, the Policia Foral and Municipal Police form lines on Mercaderes that define the waiting zone for runners. Runners must be positioned between the start on Santo Domingo and a point halfway down Mercaderes before the course is cleared. Between approximately 7:50 and 7:55 AM, after the third playing of the official warnings, the police line on Mercaderes moves aside and runners are free to take their positions further up the course.
Vocabulario: Key Spanish Terms for Mercaderes
Mercaderes (mer-cah-DEH-res): “Merchants’ Street,” the section of the encierro route connecting the Plaza del Ayuntamiento to La Curva de Estafeta.
Barreras (bah-REH-ras): The wooden barriers lining the route that serve as both crowd control and emergency escape points for runners.
Mozo (MOH-tho): A runner in the encierro. The term applies equally to first-timers and veterans.
Adoquines (ah-doh-KEE-nes): The cobblestones that pave the encierro route, whose surface condition (wet or dry) directly affects bull and runner traction.
La Curva de Estafeta (lah COOR-vah deh es-tah-FEH-tah): The sharp right turn from Mercaderes into Calle Estafeta, the most famous single point on the route.
Frequently Asked Questions
How long is the Mercaderes section of the encierro?
Mercaderes is approximately 50 meters long, making it one of the shortest named sections of the 875-meter encierro route. Despite its brevity, the narrowing street and downhill gradient make it a section that requires full attention from runners.
Where should a first-time runner position themselves on Mercaderes?
First-time runners should be aware that Mercaderes feeds directly into La Curva de Estafeta, one of the most intense points on the route. If you choose to run here, the left side of Mercaderes is generally less exposed to the herd’s natural drift pattern. Regardless of position, never stand still. Be moving before the bulls reach you.
What time do runners need to be in position on Mercaderes?
Runners must be within the official waiting zone (between Santo Domingo and halfway down Mercaderes) before 7:30 AM when the official gates close. The police line on Mercaderes moves aside between approximately 7:50 and 7:55 AM, allowing runners to proceed to their chosen starting positions further up the course.
Why do the bulls drift to the right on Mercaderes?
The bulls carry momentum from the diagonal crossing of the Plaza del Ayuntamiento, which pushes them toward the right. The slight camber of Mercaderes and the downhill gradient add to this drift. On wet mornings, the effect is amplified as the slick cobblestones reduce traction and exaggerate lateral movement.
Walk the Route with Runners Who Know Every Meter
Mercaderes is 50 meters of cobblestone that most people experience from a photograph. We experience it at 8:00 AM with bulls at our backs. Our instructional walking tours of the encierro route cover every section, from the corrales to the final stretch, with the perspective that only comes from years of running it. Book a tour with Encierro and learn the route from the street level.