diff --git a/src/conversions.rs b/src/conversions.rs
index 271c775..c02dde9 100644
--- a/src/conversions.rs
+++ b/src/conversions.rs
@@ -23,6 +23,9 @@ fn get_conversion(unit: NonMetric) -> Conversion {
 	let imperial_gallon_from = 100_000.0;
 	let imperial_gallon_to = 454609.0;
 
+	let us_gallon_from = inch_from * inch_from * inch_from;
+	let us_gallon_to = 231.0 * inch_to * inch_to * inch_to * 1000.0;
+
 	match unit {
 		// Length
 		NonMetric::Inch => Conversion {
@@ -120,6 +123,11 @@ fn get_conversion(unit: NonMetric) -> Conversion {
 			from: imperial_gallon_from,
 			to: MetricQuantity { amount: imperial_gallon_to, unit: Metric::Litre },
 		},
+		NonMetric::USGallon => Conversion {
+			offset: 0.0,
+			from: us_gallon_from,
+			to: MetricQuantity { amount: us_gallon_to, unit: Metric::Litre },
+		},
 	}
 }
 
@@ -195,6 +203,7 @@ mod test {
 			Test(NonMetric::ImperialPint, 0.56826125),
 			Test(NonMetric::ImperialQuart, 1.1365225),
 			Test(NonMetric::ImperialGallon, 4.54609),
+			Test(NonMetric::USGallon, 3.785411784),
 		];
 		run_tests(&tests, Metric::Litre);
 	}
diff --git a/src/lib.rs b/src/lib.rs
index 13d6972..d2e1d0a 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -89,6 +89,7 @@ fn unit_to_name(unit: NonMetric) -> &'static str {
 		NonMetric::ImperialPint => "imperial pints",
 		NonMetric::ImperialQuart => "imperial quarts",
 		NonMetric::ImperialGallon => "imperial gallons",
+		NonMetric::USGallon => "US gallons",
 	}
 }
 
@@ -135,5 +136,6 @@ mod test {
 		assert_eq!(run("1 imp pt"), Ok("5.683 dl".to_string()));
 		assert_eq!(run("1 imp qt"), Ok("1.137 l".to_string()));
 		assert_eq!(run("1 imp gal"), Ok("4.546 l".to_string()));
+		assert_eq!(run("1 US gal"), Ok("3.785 l".to_string()));
 	}
 }
diff --git a/src/parse.rs b/src/parse.rs
index 555ac41..e5fe566 100644
--- a/src/parse.rs
+++ b/src/parse.rs
@@ -204,6 +204,13 @@ fn parse_unit(input: String) -> Result<NonMetric, ParseError> {
 		"imperial gallons" => Ok(NonMetric::ImperialGallon),
 		"imp gal" => Ok(NonMetric::ImperialGallon),
 
+		"US gallon" => Ok(NonMetric::USGallon),
+		"US gallons" => Ok(NonMetric::USGallon),
+		"US gal" => Ok(NonMetric::USGallon),
+		"us gallon" => Ok(NonMetric::USGallon),
+		"us gallons" => Ok(NonMetric::USGallon),
+		"us gal" => Ok(NonMetric::USGallon),
+
 		_ => Err(ParseError::UnknownUnit(input)),
 	}
 }
@@ -457,6 +464,13 @@ mod test {
 		assert_eq!(parse_unit("imperial gallons".to_string()), Ok(NonMetric::ImperialGallon));
 		assert_eq!(parse_unit("imp gal".to_string()), Ok(NonMetric::ImperialGallon));
 
+		assert_eq!(parse_unit("US gallon".to_string()), Ok(NonMetric::USGallon));
+		assert_eq!(parse_unit("US gallons".to_string()), Ok(NonMetric::USGallon));
+		assert_eq!(parse_unit("US gal".to_string()), Ok(NonMetric::USGallon));
+		assert_eq!(parse_unit("us gallon".to_string()), Ok(NonMetric::USGallon));
+		assert_eq!(parse_unit("us gallons".to_string()), Ok(NonMetric::USGallon));
+		assert_eq!(parse_unit("us gal".to_string()), Ok(NonMetric::USGallon));
+
 		// Unknown unit
 		assert_eq!(parse_unit("hutenosa".to_string()), Err(ParseError::UnknownUnit("hutenosa".to_string())));
 	}
diff --git a/src/units.rs b/src/units.rs
index 4a69fb5..92ce66c 100644
--- a/src/units.rs
+++ b/src/units.rs
@@ -34,6 +34,7 @@ pub enum NonMetric {
 	ImperialPint,
 	ImperialQuart,
 	ImperialGallon,
+	USGallon,
 }
 
 #[derive(Clone, Copy, Debug, PartialEq)]