diff --git a/cpp/include/cudf/io/detail/json.hpp b/cpp/include/cudf/io/detail/json.hpp
index 7ab8906e5a9..69b26a7b70a 100644
--- a/cpp/include/cudf/io/detail/json.hpp
+++ b/cpp/include/cudf/io/detail/json.hpp
@@ -14,11 +14,6 @@
  * limitations under the License.
  */
 
-/**
- * @file json.hpp
- * @brief cuDF-IO reader classes API
- */
-
 #pragma once
 
 #include <cudf/io/json.hpp>
@@ -33,10 +28,10 @@ namespace json {
 /**
  * @brief Reads and returns the entire data set.
  *
- * @param[in] sources Input `datasource` objects to read the dataset from
- * @param[in] options Settings for controlling reading behavior
- * @param[in] stream CUDA stream used for device memory operations and kernel launches
- * @param[in] mr Device memory resource to use for device memory allocation
+ * @param sources Input `datasource` objects to read the dataset from
+ * @param options Settings for controlling reading behavior
+ * @param stream CUDA stream used for device memory operations and kernel launches
+ * @param mr Device memory resource to use for device memory allocation
  *
  * @return cudf::table object that contains the array of cudf::column.
  */
diff --git a/cpp/src/io/json/reader_impl.cu b/cpp/src/io/json/reader_impl.cu
index 0d819930ac9..319906111af 100644
--- a/cpp/src/io/json/reader_impl.cu
+++ b/cpp/src/io/json/reader_impl.cu
@@ -345,7 +345,7 @@ std::pair<std::vector<std::string>, col_map_ptr_type> get_column_names_and_map(
   rmm::cuda_stream_view stream)
 {
   // If file only contains one row, use the file size for the row size
-  uint64_t first_row_len = d_data.size() / sizeof(char);
+  uint64_t first_row_len = d_data.size();
   if (rec_starts.size() > 1) {
     // Set first_row_len to the offset of the second row, if it exists
     CUDA_TRY(cudaMemcpyAsync(&first_row_len,