diff --git a/include/libopencm3/stm32/l4/usart.h b/include/libopencm3/stm32/l4/usart.h
new file mode 100644
index 00000000..f7c79619
--- /dev/null
+++ b/include/libopencm3/stm32/l4/usart.h
@@ -0,0 +1,50 @@
+/** @defgroup usart_defines USART Defines
+ *
+ * @brief Defined Constants and Types for the STM32L4xx USART
+ *
+ * @ingroup STM32L4xx_defines
+ *
+ * LGPL License Terms @ref lgpl_license
+ */
+
+/*
+ * This file is part of the libopencm3 project.
+ *
+ * This library is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library. If not, see .
+ */
+
+#ifndef LIBOPENCM3_USART_H
+#define LIBOPENCM3_USART_H
+
+#include
+#include
+
+/** @defgroup usart_reg_base USART register base addresses
+ * @ingroup STM32F_usart_defines
+ * Holds all the U(S)ART peripherals supported.
+ * @{
+ */
+#define USART1 USART1_BASE
+#define USART2 USART2_BASE
+#define USART3 USART2_BASE
+#define UART4 USART4_BASE
+#define UART5 USART5_BASE
+#define LPUART1 LPUART1_BASE
+/**@}*/
+
+BEGIN_DECLS
+
+END_DECLS
+
+#endif