How Much Of Florida Is Below Sea Level?

With hundreds of miles of coastline and low elevation, Florida faces a constant threat from rising seas. But exactly how much of the Sunshine State lies below the ocean’s surface? As seas rise, this question takes on new urgency. Keep reading to learn what percentage of Florida falls under the sea level benchmark.

If you’re short on time, here’s a quick answer to your question: Only a very small percentage of Florida is below sea level. Less than 5% of the state’s total area lies below sea level.

Defining Sea Level

Before delving into how much of Florida is below sea level, it is important to understand what exactly is meant by “sea level.” Sea level refers to the average height of the ocean’s surface at a given location.

It serves as a baseline for measuring the elevation of landmasses and is used as a reference point for determining changes in sea levels over time.

Mean Sea Level

The term “mean sea level” (MSL) is commonly used in discussions about sea level rise and its impact on coastal areas. MSL is the average height of the ocean’s surface over a specific period of time, typically measured over several years.

It takes into account variations caused by factors such as tides, seasonal changes, and weather patterns.

MSL is determined through the use of tide gauges, which are devices that measure the height of the water surface relative to a fixed point on land. These measurements are collected over extended periods and averaged to calculate the mean sea level for a given location.

Sea Level Datums

Sea level datums are reference points used to measure elevations above or below sea level. They provide a standardized framework for comparing and interpreting elevation data across different locations.

In the United States, the most commonly used sea level datum is the North American Vertical Datum of 1988 (NAVD88).

NAVD88 is based on a network of benchmarks and tide gauges that have been carefully surveyed and monitored. It serves as a benchmark for determining elevations and is used by various government agencies, including the National Oceanic and Atmospheric Administration (NOAA), for mapping and land surveying purposes.

It is worth noting that sea level datums can vary depending on the region and the purpose for which they are being used. Different countries may have their own national datums, and local datums may be established for specific areas or projects.

For more detailed information on sea level and its measurement, the NOAA website provides a wealth of resources and data:

Florida’s Elevation Profile

Low-Lying Geography

Florida is known for its beautiful beaches, stunning landscapes, and unique wildlife. However, one aspect that sets it apart from other states is its low-lying geography. A significant portion of Florida is located below sea level, making it vulnerable to the effects of rising sea levels and coastal erosion.

The state’s flat terrain and porous limestone bedrock contribute to its susceptibility to flooding and saltwater intrusion. Florida’s low elevation also makes it prone to storm surges during hurricanes, which can cause significant damage to coastal communities.

It’s important to note that not all of Florida is below sea level. The southern part of the state, including areas like Miami and the Florida Keys, is particularly vulnerable due to its proximity to the Atlantic Ocean and the Gulf of Mexico.

However, other parts of Florida, such as the central and northern regions, have slightly higher elevations.

Elevation Statistics

According to data from the United States Geological Survey (USGS), the average elevation of Florida is about 100 feet above sea level. However, this average can be misleading, as there are areas in the state that are significantly lower in elevation.

Some of the lowest points in Florida include the Everglades, which have an average elevation of just 8 feet above sea level, and Lake Okeechobee, the largest freshwater lake in the state, which has an average depth of about 9 feet.

When it comes to cities, Miami has an average elevation of only 6 feet above sea level, while Key West, the southernmost point of the continental United States, sits at just 3 feet above sea level.

It’s important for residents and policymakers in Florida to be aware of the state’s low-lying geography and take appropriate measures to mitigate the potential impacts of rising sea levels. This includes implementing coastal management strategies, investing in infrastructure improvements, and promoting sustainable development practices.

For more information on Florida’s elevation profile and the potential risks associated with rising sea levels, you can visit the United States Geological Survey website.

Measuring Florida’s Area Below Sea Level

Florida, known for its beautiful beaches and sunny weather, is a state that faces unique geographical challenges due to its low-lying terrain. A significant portion of Florida’s land is actually below sea level, making it vulnerable to flooding and other environmental concerns.

In this article, we will explore how Florida’s area below sea level is measured and the percentage of land that is affected.

Mapping Elevations

Mapping the elevations of Florida’s terrain is a complex task that involves the use of advanced technology and precise measurements. Geographers and surveyors utilize tools such as LiDAR (Light Detection and Ranging) to accurately determine the elevation of different areas.

LiDAR uses laser beams to measure the distance between the ground and the sensor, creating a detailed elevation map of the land.

By mapping elevations, scientists can identify areas that are below sea level and understand the extent of the problem. This information is crucial for urban planning, emergency management, and environmental conservation efforts.

Percentage Below Sea Level

When it comes to determining the percentage of Florida’s land that is below sea level, it is important to consider the varying elevations across the state. According to the United States Geological Survey (USGS), approximately 18% of Florida’s land is below the mean high-water level, which includes both tidal and non-tidal water bodies.

However, it is worth noting that the percentage of land below sea level can vary based on factors such as coastal erosion, climate change, and natural geological processes. Rising sea levels due to global warming also pose a significant threat to Florida’s low-lying coastal areas.

Did you know? The Everglades, a unique and ecologically rich wetland in Florida, is one of the most prominent areas below sea level in the state. Its average elevation is about 6 feet (1.8 meters) below sea level, making it vulnerable to flooding and environmental changes.

Impacts of Rising Seas

Increasing Flood Risk

As the sea levels continue to rise, the risk of floods in coastal areas of Florida is significantly increasing. The state is particularly vulnerable due to its low-lying topography. According to a report by the Union of Concerned Scientists, it is estimated that by 2050, over 300,000 Florida homes, worth approximately $145 billion, will be at risk of chronic flooding.

This poses a serious threat not only to the residents but also to the economy of the state.

The increasing flood risk is not limited to coastal communities alone. Inland areas can also experience flooding as rising seas can lead to higher water tables and increased vulnerability to heavy rainfall events.

This can result in damage to infrastructure, loss of property, and disruption of daily life.

Efforts to mitigate flood risk include the construction of seawalls, levees, and other coastal defense systems. However, these measures are not foolproof and can be costly to implement and maintain. Additionally, they may also have unintended consequences, such as altering natural coastal processes and impacting ecosystems.

Effects on Populations

Rising sea levels also have significant impacts on the population of Florida. Coastal communities are at risk of displacement as their homes and neighborhoods become uninhabitable due to flooding. This can lead to the forced relocation of residents, causing social and economic disruptions.

Furthermore, many vulnerable populations, such as low-income communities and minority groups, are disproportionately affected by rising seas. These communities often lack the resources and infrastructure necessary to adapt to or recover from the impacts of flooding.

This exacerbates existing social inequalities and can result in long-term consequences for the affected individuals and communities.

The effects of rising seas on populations extend beyond immediate displacement. They can also lead to increased migration as people seek safer areas to live. This can put additional pressure on already crowded cities and impact the demographics and social fabric of both receiving and sending communities.

It is crucial for policymakers and stakeholders to address the impacts of rising seas on populations and develop comprehensive strategies for adaptation and resilience. This includes investing in infrastructure, promoting equitable access to resources, and engaging with affected communities in decision-making processes.

For more information on the impacts of rising seas, you can visit the website of the Union of Concerned Scientists.


Although only a small fraction of Florida currently sits below sea level, even gradual rises in ocean levels have an outsized impact on this low-lying state. Understanding the extent of vulnerable below-sea-level areas can help Florida better prepare coastal communities for the effects of climate change-driven sea level rise.

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