diff --git a/crates/ethereum/cli/src/chainspec.rs b/crates/ethereum/cli/src/chainspec.rs
index 419ff71cb..24151fe2f 100644
--- a/crates/ethereum/cli/src/chainspec.rs
+++ b/crates/ethereum/cli/src/chainspec.rs
@@ -8,7 +8,7 @@ use reth_primitives::{Header, SealedHeader};
 use std::sync::Arc;
 
 /// Chains supported by reth. First value should be used as the default.
-pub const SUPPORTED_CHAINS: &[&str] = &["mainnet", "sepolia", "holesky", "dev"];
+pub const SUPPORTED_CHAINS: &[&str] = &["mainnet", "testnet", "sepolia", "holesky", "dev"];
 
 static GENESIS_HASH: B256 =
     b256!("d8fcc13b6a195b88b7b2da3722ff6cad767b13a8c1e9ffb1c73aa9d216d895f0");
@@ -92,6 +92,7 @@ pub static HL_MAINNET: Lazy<alloc::sync::Arc<ChainSpec>> = Lazy::new(|| {
 pub fn chain_value_parser(s: &str) -> eyre::Result<Arc<ChainSpec>, eyre::Error> {
     Ok(match s {
         "mainnet" => HL_MAINNET.clone(),
+        "testnet" => Arc::new(super::hl_testnet::load_hl_testnet()),
         "sepolia" => SEPOLIA.clone(),
         "holesky" => HOLESKY.clone(),
         "dev" => DEV.clone(),
diff --git a/crates/ethereum/cli/src/hl_testnet.rs b/crates/ethereum/cli/src/hl_testnet.rs
new file mode 100644
index 000000000..4f52ad5b1
--- /dev/null
+++ b/crates/ethereum/cli/src/hl_testnet.rs
@@ -0,0 +1,113 @@
+use alloy_consensus::Header;
+use alloy_genesis::{ChainConfig, Genesis};
+use alloy_primitives::U256;
+use alloy_rlp::Decodable;
+use reqwest::blocking::get;
+use reth_chainspec::{ChainSpec, DEV_HARDFORKS};
+use reth_primitives::SealedHeader;
+use std::collections::BTreeMap;
+use std::fs::File;
+use std::io::{Read, Write};
+
+pub(crate) fn load_hl_testnet() -> ChainSpec {
+    const TESTNET_GENESIS_URL: &str = "https://raw.githubusercontent.com/sprites0/hl-testnet-genesis/main/19386700.rlp";
+
+    fn download_testnet_genesis() -> Result<&'static str, Box<dyn std::error::Error>> {
+        let path = "/tmp/hl_testnet.rmp.lz4";
+        println!("Downloading testnet genesis");
+        let mut response = get(TESTNET_GENESIS_URL)?;
+        if let Some(length) = response.content_length() {
+            // Check if the file exists
+            if let Ok(metadata) = std::fs::metadata(path) {
+                if metadata.len() == length {
+                    println!("Already downloaded");
+                    return Ok(path);
+                }
+            }
+        }
+        let mut file = File::create(path)?;
+        let mut downloaded = 0;
+        let total_size = response.content_length().unwrap_or(0);
+        let mut buffer = vec![0; 0x100000];
+
+        loop {
+            let size = response.read(buffer.as_mut_slice())?;
+            if size == 0 {
+                break;
+            }
+            file.write_all(&buffer[..size])?;
+            downloaded += size as u64;
+            println!(
+                "Downloaded {} of {} bytes ({}%)",
+                downloaded,
+                total_size,
+                (downloaded as f64 / total_size as f64 * 100.0).round()
+            );
+        }
+        Ok(path)
+    }
+
+    let path = download_testnet_genesis().expect("Failed to download testnet genesis");
+    let mut file = File::open(path).expect("Failed to open testnet genesis");
+    let mut buffer = Vec::new();
+    file.read_to_end(&mut buffer).expect("Failed to read testnet genesis");
+    let mut header = Header::decode(&mut &buffer[..]).expect("Failed to decode testnet genesis");
+
+    let config = ChainConfig {
+        chain_id: 998,
+        homestead_block: Some(0),
+        dao_fork_block: Some(0),
+        dao_fork_support: false,
+        eip150_block: Some(0),
+        eip155_block: Some(0),
+        eip158_block: Some(0),
+        byzantium_block: Some(0),
+        constantinople_block: Some(0),
+        petersburg_block: Some(0),
+        istanbul_block: Some(0),
+        muir_glacier_block: Some(0),
+        berlin_block: Some(0),
+        london_block: Some(0),
+        arrow_glacier_block: Some(0),
+        gray_glacier_block: Some(0),
+        merge_netsplit_block: Some(0),
+        shanghai_time: Some(0),
+        cancun_time: Some(0),
+        prague_time: Some(0),
+        osaka_time: Some(0),
+        terminal_total_difficulty: Some(U256::ZERO),
+        terminal_total_difficulty_passed: true,
+        ethash: None,
+        clique: None,
+        parlia: None,
+        extra_fields: Default::default(),
+        deposit_contract_address: None,
+        blob_schedule: Default::default(),
+    };
+    header.number = 0;
+    let genesis_header = SealedHeader::new(header.clone(), header.hash_slow());
+    let genesis = Genesis {
+        config,
+        nonce: header.nonce.into(),
+        timestamp: header.timestamp,
+        extra_data: header.extra_data,
+        gas_limit: header.gas_limit,
+        difficulty: header.difficulty,
+        mix_hash: header.mix_hash,
+        coinbase: header.beneficiary,
+        alloc: BTreeMap::default(),
+        base_fee_per_gas: header.base_fee_per_gas.map(|x| x.into()),
+        excess_blob_gas: header.excess_blob_gas,
+        blob_gas_used: header.blob_gas_used,
+        number: None,
+    };
+
+    ChainSpec {
+        chain: alloy_chains::Chain::from_id(998),
+        genesis: genesis.into(),
+        genesis_header,
+        hardforks: DEV_HARDFORKS.clone(),
+        prune_delete_limit: 10000,
+        ..Default::default()
+    }
+}
diff --git a/crates/ethereum/cli/src/lib.rs b/crates/ethereum/cli/src/lib.rs
index 7296e7c2d..dcdfcdb03 100644
--- a/crates/ethereum/cli/src/lib.rs
+++ b/crates/ethereum/cli/src/lib.rs
@@ -11,6 +11,8 @@
 /// Chain specification parser.
 pub mod chainspec;
 
+mod hl_testnet;
+
 #[cfg(test)]
 mod test {
     use clap::Parser;